| 1. |
- Engel, Jörgen, 1942, et al.
(författare)
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Neonatal herpes simplex virus type 1 brain infection affects the development of sensorimotor gating in rats.
- 2000
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Ingår i: Brain research. - 0006-8993. ; 863:1-2, s. 233-40
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Tidskriftsartikel (refereegranskat)abstract
- The effect of neonatal brain infection of herpes simplex virus type 1 (HSV-1) on the development of sensorimotor function in the rat was investigated using an acoustic startle paradigm. Intracerebral inoculation of HSV-1 at day 2 after birth, but not at day 4, caused a significant delay in the development of prepulse inhibition of acoustic startle. A decrease in prepulse inhibition was shown at 37, 46 and 58 days of age in these rats compared to control rats. No evidence was obtained for other behavioural dysfunctions such as differences in sensorimotor reactivity, sensorimotor response habituation, spontaneous locomotor activity, rearing activity or stereotyped behaviour. Prepulse inhibition of acoustic startle is an accepted model of sensorimotor gating in the CNS, a function which has been shown diminished in schizophrenic persons. The present results suggest that early viral infections during a neurone-susceptible period may contribute to the development of this deficit.
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| 2. |
- Ericsson, Peter, et al.
(författare)
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ECL Cell Histamine Mobilization Studied byGastric Submucosal Microdialysis in Awake Rats:Methodological Considerations.
- 2003
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Ingår i: Pharmacology and Toxicology. - : Wiley. - 1600-0773 .- 0901-9928. ; 93:2, s. 57-65
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Tidskriftsartikel (refereegranskat)abstract
- The ECL cells are endocrine/paracrine cells in the acid-producing part of the stomach. They secrete histamine in response to circulating gastrin. Gastric submucosal microdialysis has been used to study ECL-cell histamine mobilization in awake rats. In the present study we assess the usefulness and limitations of the technique. Microdialysis probes were implanted in the gastric submucosa. Histological analysis of the stomach wall around the probe revealed a moderate, local inflammatory reaction 1-2 days after implantation; the inflammation persisted for at least 10 days. Experiments were conducted 3 days after the implantation. The "true" submucosal histamine concentration was determined by perfusing at different rates (the zero flow method) or with different concentrations of histamine at a constant rate (the no-net-flux method): in fasted rats it was calculated to be 87±5 (means±S.E.M.) nmol/l and 76±9 nmol/l, respectively. The corresponding histamine concentrations in fed rats were 93±5 and 102±8 nmol/l, respectively. With a perfusion rate of 74 mul/hr the recovery of submucosal histamine was 49%, at 34 mul/hr the recovery increased to 83%. At a perfusion rate below 20 mul/hr the microdialysate histamine concentration was close to the actual concentration in the submucosa. The ECL-cell histamine mobilization was independent of the concentrations of Ca2+ in the perfusion medium (0-3.4 mmol/l Ca2+). In one experiment, histamine mobilization in response to gastrin (10 nmol/kg/hr subcutaneously) was monitored in rats pretreated with prednisolone (60 mg/kg) or indomethacin (15 mg/kg). The two antiinflammatory agents failed to affect the concentration of histamine in the microdialysate either before or during the gastrin challenge, which was in accord with the observation that the inflammatory reaction was modest and that inflammatory cells were relatively few around the probe and in the wall of the probe. In another experiment, rats were given aminoguanidine (10 mg/kg) or metoprine (10 mg/kg) 4 hr before the start of gastrin infusion (5 nmol/kg/hr intravenously). Metoprine (inhibitor of histamine N-methyl transferase) did not affect the microdialysate histamine concentration, while aminoguanidine (inhibitor of diamine oxidase) raised both basal and gastrin-stimulated histamine concentrations. We conclude that microdialysis can be used to monitor changes in the concentration of histamine in the submucosa of the stomach, and that the inflammatory reaction to the probe is moderate and does not affect the submucosal histamine mobilization.
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| 3. |
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| 4. |
- Movahed Rad, Pouya, et al.
(författare)
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Endogenous unsaturated C18 N-acylethanolamines are vanilloid receptor (TRPV1) agonists.
- 2005
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Ingår i: Journal of Biological Chemistry. - 1083-351X .- 0021-9258. ; 280:46, s. 38496-38504
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Tidskriftsartikel (refereegranskat)abstract
- The endogenous C18 N-acylethanolamines (NAEs) N-linolenoylethanolamine (18:3 NAE), N-linoleoylethanolamine (18:2 NAE), N-oleoylethanolamine (18:1 NAE), and N-stearoylethanolamine (18:0 NAE) are structurally related to the endocannabinoid anandamide (20:4 NAE), but these lipids are poor ligands at cannabinoid CB1 receptors. Anandamide is also an activator of the transient receptor potential (TRP) vanilloid 1 (TRPV1) on primary sensory neurons. Here we show that C18 NAEs are present in rat sensory ganglia and vascular tissue. With the exception of 18:3 NAE in rat sensory ganglia, the levels of C18 NAEs are equal to or substantially exceed those of anandamide. At submicromolar concentrations, 18:3 NAE, 18:2 NAE, and 18:1 NAE, but not 18:0 NAE and oleic acid, activate native rTRPV1 on perivascular sensory nerves. 18:1 NAE does not activate these nerves in TRPV1 gene knock-out mice. Only the unsaturated C18 NAEs elicit whole cell currents and fluorometric calcium responses in HEK293 cells expressing hTRPV1. Molecular modeling revealed a low energy cluster of U-shaped unsaturated NAE conformers, sharing several pharmacophoric elements with capsaicin. Furthermore, one of the two major low energy conformational families of anandamide also overlaps with the cannabinoid CB1 receptor ligand HU210, which is in line with anandamide being a dual activator of TRPV1 and the cannabinoid CB1 receptor. This study shows that several endogenous non-cannabinoid NAEs, many of which are more abundant than anandamide in rat tissues, activate TRPV1 and thus may play a role as endogenous TRPV1 modulators.
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| 5. |
- Vincents, Bjarne, et al.
(författare)
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Down-regulation of human extracellular cysteine protease inhibitors by the secreted staphylococcal cysteine proteases, staphopain A and B.
- 2007
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Ingår i: Biological Chemistry. - 1437-4315. ; 388:4, s. 437-446
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Tidskriftsartikel (refereegranskat)abstract
- Of seven human cystatins investigated, none inhibited the cysteine proteases staphopain A and B secreted by the human pathogen Staphylococcus aureus. Rather, the extracellular cystatins C, D and E/M were hydrolyzed by both staphopains. Based on MALDI-TOF time-course experiments, staphopain A cleavage of cystatin C and D should be physiologically relevant and occur upon S. aureus infection. Staphopain A hydrolyzed the Glyl 1 bond of cystatin C and the Ala10 bond of cystatin D with similar K-m values of approximately 33 and 32 mu m, respectively. Such N-terminal truncation of cystatin C caused > 300-fold lower inhibition of papain, cathepsin B, L and K, whereas the cathepsin H activity was compromised by a factor of ca. 10. Similarly, truncation of cystatin D caused alleviated inhibition of all endogenous target enzymes investigated. The normal activity of the cystatins is thus down-regulated, indicating that the bacterial enzymes can cause disturbance of the host protease-inhibitor balance. To illustrate the in vivo consequences, a mixed cystatin C assay showed release of cathepsin B activity in the presence of staphopain A. Results presented for the specificity of staphopains when interacting with cystatins as natural protein substrates could aid in the development of therapeutic agents directed toward these proteolytic virulence factors.
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| 6. |
- Persson, Carl, et al.
(författare)
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Unbalanced research
- 2001
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Ingår i: Trends in Pharmacological Sciences. - 0165-6147. ; 22:10, s. 538-541
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Tidskriftsartikel (refereegranskat)
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| 7. |
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| 8. |
- Birnir, Bryndis, et al.
(författare)
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Bicuculline, pentobarbital and diazepam modulate spontaneous GABA(A) channels in rat hippocampal neurons
- 2000
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Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 131:4, s. 695-704
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Tidskriftsartikel (refereegranskat)abstract
- Spontaneously opening, chloride-selective channels that showed outward rectification were recorded in ripped-off patches from rat cultured hippocampal neurons and in cell-attached patches from rat hippocampal CA1 pyramidal neurons in slices. In both preparations, channels had multiple conductance states and the most common single-channel conductance varied. In the outside-out patches it ranged from 12 to 70 pS (Vp=40 mV) whereas in the cell-attached patches it ranged from 56 to 85 pS (-Vp=80 mV). Application of GABA to a patch showing spontaneous channel activity evoked a rapid, synchronous activation of channels. During prolonged exposure to either 5 or 100 microM GABA, the open probability of channels decreased. Application of GABA appeared to have no immediate effect on single-channel conductance. Exposure of the patches to 100 microM bicuculline caused a gradual decrease on the single-channel conductance of the spontaneous channels. The time for complete inhibition to take place was slower in the outside-out than in the cell-attached patches. Application of 100 microM pentobarbital or 1 microM diazepam caused 2 - 4 fold increase in the maximum channel conductance of low conductance (<40 pS) spontaneously active channels. The observation of spontaneously opening GABA(A) channels in cell-attached patches on neurons in slices suggests that they may have a role in neurons in vivo and could be an important site of action for some drugs such as benzodiazepines, barbiturates and general anaesthetics.
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| 9. |
- Eghbali, M, et al.
(författare)
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Pentobarbital modulates gamma-aminobutyric acid-activated single-channel conductance in rat cultured hippocampal neurons.
- 2000
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Ingår i: Molecular Pharmacology. - 0026-895X .- 1521-0111. ; 58:3, s. 463-9
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Tidskriftsartikel (refereegranskat)abstract
- We examined the effect of a range of pentobarbital concentrations on 0.5 microM gamma-aminobutyric acid (GABA)-activated channels (10 +/- 1 pS) in inside-out or outside-out patches from rat cultured hippocampal neurons. The conductance increased from 12 +/- 4 to 62 +/- 9 pS as the pentobarbital concentration was raised from 10 to 500 microM and the data could be fitted by a Hill-type equation. At 100 microM pentobarbital plus 0.5 microM GABA, the conductance seemed to reach a plateau. The pentobarbital EC(50)(0.5 microM GABA) value was 22 +/- 4 microM and n was 1.9 +/- 0.5. In 1 mM pentobarbital plus 0.5 microM GABA, the single-channel conductance decreased to 34 +/- 8 pS. This apparent inhibition of channel conductance was relieved by 1 microM diazepam. The channel conductance was 64 +/- 6 pS in the presence of all three drugs. The channels were open more in the presence of both GABA and pentobarbital than in the presence of either drug alone. Pentobarbital alone (100 microM) activated channels with conductance (30 +/- 2 pS) and kinetic properties distinct from those activated by either GABA alone or GABA plus pentobarbital. Whether pentobarbital induces new conformations or promotes conformations observed in the presence of GABA alone cannot be determined from our study, but the results clearly show that it is the combination of drugs present that determines the single-channel conductance and the kinetic properties of the receptors.
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| 10. |
- Fälker, Knut, 1971-, et al.
(författare)
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ADP secretion and subsequent P2Y12 receptor signalling play a crucial role in thrombin-induced ERK2 activation in human platelets
- 2004
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Ingår i: Thrombosis and Haemostasis. - Stuttgart, Germany : Schattauer Gmbh. - 0340-6245 .- 2567-689X. ; 92:1, s. 114-23
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Tidskriftsartikel (refereegranskat)abstract
- Stimulating human platelets with thrombin induces the activation of the extracellular signal-regulated kinase 2 (ERK2). We demonstrate that this effect is highly dependent on ADP secretion and P2Y12 receptor signalling. AR-C69931MX (10 microM), a specific antagonist of the Gi-coupled P2Y12 ADP receptor, inhibits ERK2 activation induced by thrombin. Antagonists of the Gq-coupled P2Y1 ADP receptor, A3P5P (500 microM) and MRS2179 (100 microM), have no effect. ADP and its more potent analogue 2-methylthio-ADP alone (both up to 100 microM) do not induce ERK2 activation. Furthermore, we show that the inhibitory effect of AR-C69931MX on ERK2 activation induced by 0.1 U/ml thrombin as well as on platelet aggregation can be bypassed by epinephrine (1 and 10 microM), whereas epinephrine alone has no effect. Epinephrine acts on platelets mainly via alpha(2A)-adrenergic receptors, which, like P2Y12 receptors, couple to inhibitory G proteins. In addition, 2-methylthio-ADP as well as epinephrine provoke ERK2 activation at a thrombin concentration that alone has no detectable effect (0.05 U/ml). Thromboxane A2 (TXA2), which, like ADP, is released by activated platelets, acts as a positive feedback mediator. Stimulating the Gq-coupled TXA2 -receptor with U46619 (10 microM), which leads to ADP secretion and P2Y12 receptor-dependent platelet aggregation, also induces P2Y12-related ERK2 activation. The inhibition of U46619-induced ERK2 activation and platelet aggregation by AR-C69931MX are also rescued by epinephrine. Pretreatment with aspirin inhibits ERK2 activation induced by 0.1 U/ml thrombin, but has no effect at high concentrations of thrombin. The combination of U46619 and thrombin, at concentrations which alone have no effect, provokes ERK2 activation, suggesting that thrombin and released TXA2 act synergistically. Our data indicate that both primary signalling through Gq, which evokes ADP secretion, as well as subsequent coupling via Gi by the P2Y12 receptor are required for ERK2 activation.
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| 11. |
- Brage, M, et al.
(författare)
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Different cysteine proteinases involved in bone resorption and osteoclast formation.
- 2005
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Ingår i: Calcified tissue international. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 76:6, s. 439-47
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Tidskriftsartikel (refereegranskat)abstract
- Cysteine proteinases, especially cathepsin K, play an important role in osteoclastic degradation of bone matrix proteins and the process can, consequently, be significantly inhibited by cysteine proteinase inhibitors. We have recently reported that cystatin C and other cysteine proteinase inhibitors also reduce osteoclast formation. However, it is not known which cysteine proteinase(s) are involved in osteoclast differentiation. In the present study, we compared the relative potencies of cystatins C and D as inhibitors of bone resorption in cultured mouse calvariae, osteoclastogenesis in mouse bone marrow cultures, and cathepsin K activity. Inhibition of cathepsin K activity was assessed by determining equilibrium constants for inhibitor complexes in fluorogenic substrate assays. The data demonstrate that whereas human cystatins C and D are equipotent as inhibitors of bone resorption, cystatin D is 10-fold less potent as an inhibitor of osteoclastogenesis and 200-fold less potent as an inhibitor of cathepsin K activity. A recombinant human cystatin C variant with Gly substitutions for residues Arg8, Leu9, Val10, and Trp106 did not inhibit bone resorption, had 1,000-fold decreased inhibitory effect on cathepsin K activity compared to wildtype cystatin C, but was equipotent with wildtype cystatin C as an inhibitor of osteoclastogenesis. It is concluded that (i) different cysteine proteinases are likely to be involved in bone resorption and osteoclast formation, (ii) cathepsin K may not be an exclusive target enzyme in any of the two systems, and (iii) the enzyme(s) involved in osteoclastogenesis might not be a typical papain-like cysteine proteinase.
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| 12. |
- Gomez-Pinilla, Pedro J, et al.
(författare)
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Melatonin restores impaired contractility in aged guinea pig urinary bladder
- 2008
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Ingår i: Journal of Pineal Research. - : Blackwell Publishing Ltd. - 1600-079X .- 0742-3098. ; 44:4, s. 416-425
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Tidskriftsartikel (refereegranskat)abstract
- Urinary bladder disturbances are frequent in the elderly population but the responsible mechanisms are poorly understood. This study evaluates the effects of aging on detrusor myogenic contractile responses and the impact of melatonin treatment. The contractility of bladder strips from adult, aged and melatonin-treated guinea pigs was evaluated by isometric tension recordings. Cytoplasmatic calcium concentration ([Ca2+](i)) was estimated by epifluorescence microscopy of fura-2-loaded isolated detrusor smooth muscle cells, and the levels of protein expression and phosphorylation were quantitated by Western blotting. Aging impairs the contractile response of detrusor strips to cholinergic and purinergic agonists and to membrane depolarization. The impaired contractility correlates with increased [Ca2+](i) in response to the stimuli, suggesting a reduced Ca(2+)sensitivity. Indeed, the agonist-induced contractions in adult strips were sensitive to blockade with Y27362, an inhibitor of Rho kinase (ROCK) and GF109203X, an inhibitor of protein kinase C (PKC), but these inhibitors had negligible effects in aged strips. The reduced Ca2+ sensitivity in aged tissues correlated with lower levels of RhoA, ROCK, PKC and the two effectors CPI-17 and MYPT1, and with the absence of CPI-17 and MYPT1 phosphorylation in response to agonists. Interestingly, melatonin treatment restored impaired contractility via normalization of Ca2+ handling and Ca2+ sensitizations pathways. Moreover, the indoleamine restored age-induced changes in oxidative stress and mitochondrial polarity. These results suggest that melatonin might be a novel therapeutic tool to palliate aging-related urinary bladder contractile impairment.
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| 13. |
- Löfgren, Mia, et al.
(författare)
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Substrate and product dependence of force and shortening in fast and slow smooth muscle
- 2001
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Ingår i: Journal of General Physiology. - : Rockefeller University Press. - 0022-1295 .- 1540-7748. ; 117:5, s. 407-418
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Tidskriftsartikel (refereegranskat)abstract
- To explore the molecular mechanisms responsible for the variation in smooth muscle contractile kinetics, the influence of MgATP, MgADP, and inorganic phosphate (P(i)) on force and shortening velocity in thiophosphorylated "fast" (taenia coli: maximal shortening velocity Vmax = 0.11 ML/s) and "slow" (aorta: Vmax = 0.015 ML/s) smooth muscle from the guinea pig were compared. P(i) inhibited active force with minor effects on the V(max). In the taenia coli, 20 mM P(i) inhibited force by 25%. In the aorta, the effect was markedly less (< 10%), suggesting differences between fast and slow smooth muscles in the binding of P(i) or in the relative population of P(i) binding states during cycling. Lowering of MgATP reduced force and V(max). The aorta was less sensitive to reduction in MgATP (Km for Vmax: 80 microM) than the taenia coli (Km for Vmax: 350 microM). Thus, velocity is controlled by steps preceding the ATP binding and cross-bridge dissociation, and a weaker binding of ATP is not responsible for the lower V(max) in the slow muscle. MgADP inhibited force and V(max). Saturating concentrations of ADP did not completely inhibit maximal shortening velocity. The effect of ADP on Vmax was observed at lower concentrations in the aorta compared with the taenia coli, suggesting that the ADP binding to phosphorylated and cycling cross-bridges is stronger in slow compared with fast smooth muscle.
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| 14. |
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| 15. |
- van West, Dirk, et al.
(författare)
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Glucocorticoid receptor gene-based SNP analysis in patients with recurrent major depression
- 2006
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Ingår i: Neuropsychopharmacology. - : Nature Publishing Group. - 0893-133X .- 1740-634X. ; 31:3, s. 620-627
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Tidskriftsartikel (refereegranskat)abstract
- Dysregulation of the hypothalamic-pituitary-adrenal axis, one of the stress-response systems, is one of the key neurobiological features of major depression (MDD). Data supporting the notion that glucocorticoid-mediated feedback inhibition is impaired in MDD come from a multitude of studies demonstrating nonsuppression of cortisol secretion following administration of the synthetic glucocorticoid dexamethasone. We examined whether genetic variations in the glucocorticoid receptor gene (Nuclear Receptor Subfamily 3, Group C, Member 1; NR3C1) could be associated with increased susceptibility for MDD using a whole gene-based association analysis of single nucleotide polymorphisms (SNPs). Four SNPs were identified in NR3C1 and genotyped in two well-diagnosed samples of patients with MDD ascertained in Belgium and northern Sweden, and matched control samples. In total, 314 MDD patients and 354 control individuals were included in the study. In the Belgian sample, we observed significant allele (p=0.02) and genotype (p=0.02) association with an SNP in the promoter region (NR3C1-1); in the Swedish sample, we observed significant allele (p=0.02) and genotype (p=0.02) association with the R23K SNP. The haplotype association studies showed modest evidence for an involvement of the 5' region of the NR3C1 gene in the genetic vulnerability for MDD. This study suggests that polymorphisms in the 5' region of the NR3C1 gene may play a role in the genetic vulnerability for MDD.
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| 16. |
- Ripamonti, Chiara, et al.
(författare)
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Biological and genetic evolution of HIV type 1 in two siblings with different patterns of disease progression
- 2007
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Ingår i: AIDS Research and Human Retroviruses. - : Mary Ann Liebert Inc. - 1931-8405 .- 0889-2229. ; 23:12, s. 1531-1540
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the immunological and virological factors that may lead to different patterns of disease progression characteristic of HIV-1-infected children, two HIV-1-infected siblings, a slow and a fast progressor, were followed prospectively before the onset of highly active antiretroviral therapy. Viral coreceptor usage, including the use of CCR5/CXCR4 chimeric receptors, macrophage tropism, and sensitivity to the CC-chemokine RANTES, has been studied. An autologous and heterologous neutralizing antibody response has been documented using peripheral blood mononuclear cells- and GHOST(3) cell line-based assays. Viral evolution was investigated by env C2-V3 region sequence analysis. Although both siblings were infected with HIV-1 of the R5 phenotype, their viruses showed important biological differences. In the fast progressor there was a higher RANTES sensitivity of the early virus, an increased trend to change the mode of CCR5 receptor use, and a larger genetic evolution. Both children developed an autologous neutralizing antibody response starting from the second year with evidence of the continuous emergence of resistant variants. A marked viral genetic and phenotypic evolution was documented in the fast progressor sibling, which is accompanied by a high viral RANTES sensitivity and persistent neutralizing antibodies.
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| 17. |
- Magnusson, Marie, et al.
(författare)
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A placebo-controlled study of retinal blood flow changes by pentoxifylline and metabolites in humans
- 2006
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 0306-5251 .- 1365-2125. ; 61:2, s. 138-147
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To investigate the possible effects of pentoxifylline metabolites on retinal blood flow in humans. METHODS: A randomized, placebo-controlled, four-period cross-over study that was observer blinded and partly blinded for the eight participants. On one occasion a placebo was given as an intravenous (i.v.) infusion over 100 min. On the other three occasions pentoxifylline was administered as i.v. infusions over 100 min at a rate of 3 mg min(-1). Before two of the pentoxifylline infusions the subjects were pretreated with either ciprofloxacin or rifampicin. Retinal blood flow was measured by scanning laser doppler flowmetry (SLDF) in a selected area of the central temporal retina before, during and until 5 h after the end of infusion. Blood samples for concentration analyses of pentoxifyllin, R-M1, S-M1, M4 and M5 were taken serially and areas under the curves (AUCs) were calculated. Linear mixed models were used for the statistical analyses. RESULTS: Mean AUCs (ng h ml(-1)) were significantly increased for pentoxifylline (1964 vs. 1453) and S-M1 (5804 vs. 4227), but not R-M1 when pentoxifylline was co-administered with ciprofloxacin. The mean AUC for M5 was significantly reduced when subjects were pretreated with rifampicin (2041 vs. 3080). Pentoxifylline with and without pretreatment with rifampicin significantly increased retinal blood flow assessed as mean flow, pulsation (i.e. 1-systole/diastole), and diastolic flow (but not during systole), compared with placebo. The increases over placebo were more pronounced on diastolic flow, 9.7% (95% confidence interval 4.2, 15.5) than on mean flow, 4.6% (1.1, 8.3) after pentoxifylline administration. With pentoxifylline after rifampicin pretreatment the corresponding differences were 11.7% (5.8, 17.9) and 5.1% (1.4, 7.8) over placebo, respectively. After co-administration of pentoxifylline and ciprofloxacin we saw only a nonsignificant trend towards increased flow during diastole, but a significant decrease in pulsation. When AUCs for pentoxifylline and its metabolites were used as regressor variables to retinal mean flow we found that pentoxifylline, R-M1 and M5 had coefficients with a positive sign indicating that they enhanced the retinal blood flow. In contrast, S-M1 and M4 had coefficients with negative sign and thus appeared to decrease the blood flow in subjects treated with pentoxifylline. CONCLUSION: The R-M1 and M5 metabolites of pentoxifylline contributed significantly to the effects of pentoxifylline on retinal blood flow.
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| 18. |
- Rhodin, Malin M., et al.
(författare)
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Human renal function maturation : a quantitative description using weight and postmenstrual age
- 2009
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Ingår i: Pediatric nephrology (Berlin, West). - : Springer Science and Business Media LLC. - 0931-041X .- 1432-198X. ; 24:1, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- This study pools published data to describe the increase in glomerular filtration rate (GFR) from very premature neonates to young adults. The data comprises measured GFR (using polyfructose, Cr-51-EDTA, mannitol or iohexol) from eight studies (n=923) and involved very premature neonates (22 weeks postmenstrual age) to adulthood (31 years). A nonlinear mixed effects approach (NONMEM) was used to examine the influences of size and maturation on renal function. Size was the primary covariate, and GFR was standardized for a body weight of 70 kg using an allometric power model. Postmenstrual age (PMA) was a better descriptor of maturational changes than postnatal age (PNA). A sigmoid hyperbolic model described the nonlinear relationship between GFR maturation and PMA. Assuming an allometric coefficient of 3/4, the fully mature (adult) GFR is predicted to be 121.2 mL/min per 70 kg [95% confidence interval (CI) 117-125]. Half of the adult value is reached at 47.7 post-menstrual weeks (95% CI 45.1-50.5), with a Hill coefficient of 3.40 (95% CI 3.03-3.80). At 1-year postnatal age, the GFR is predicted to be 90% of the adult GFR. Glomerular filtration rate can be predicted with a consistent relationship from early prematurity to adulthood. We propose that this offers a clinically useful definition of renal function in children and young adults that is independent of the predictable changes associated with age and size.
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| 19. |
- Salomé, Nicolas, et al.
(författare)
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Anorexigenic and electrophysiological actions of novel ghrelin receptor (GHS-R1A) antagonists in rats
- 2009
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Ingår i: European Journal of Pharmacology. - : Elsevier. - 0014-2999 .- 1879-0712. ; 612:1-3, s. 167-173
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Tidskriftsartikel (refereegranskat)abstract
- Here we provide the first pharmacological exploration of the impact of acute central nervous system exposure to three recently developed ghrelin receptor (GHS-R1A) ligands on food intake and on the electrical activity of the target cells for ghrelin in the hypothalamus. Central (i.c.v) injection of GHS-R1A antagonists to rats suppressed food intake induced by i.c.v ghrelin injection (1 mu g) in a dose-dependent manner with a total blockade at concentraions of 0.4 mu g and 8 mu g for JMV 3002 and JMV 2959 respectively. JMV 2810, a partial agonist, also suppressed ghrelin-induced food intake (range: 0.02-2 mu g). Moreover all three compounds reduced fasting-induced food intake in rats (i.e. the amount of food eaten during the first hour of food exposure after a 16 h fast). At the single cell level we also explored the effects of the compounds to suppress ghrelin (0.5 mu M)-induced changes in electrical activity of arcuate nucleus cells recorded extracellularly in a slice preparation. Preincubation followed by perfusion with the GHS-R1A ligands suppressed the responsiveness of arcuate cells to ghrelin. Thus, the recently developed GHS-R1A ligands (JMV 3002, 2959 and 2810) suppress ghrelin-induced and fasting-induced food intake at the level of the central nervous system. This appears to be mediated, at least in part, by a modulation of the activity of ghrelin-responsive arcuate nucleus cells. As the central ghrelin signalling system has emerged as an important pro-obesity target, it will be important to establish the efficacy of these GHS-R1A ligands to reduce fast mass in clincal studies.
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| 20. |
- Bondesson, Åsa ÅB, et al.
(författare)
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A structured questionnaire to assess patient compliance and beliefs about medicines taking into account the ordered categorical structure of data
- 2009
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Ingår i: Journal of Evaluation In Clinical Practice. - : Wiley. - 1356-1294 .- 1365-2753. ; 15:4, s. 713-723
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Tidskriftsartikel (refereegranskat)abstract
- RATIONALE, AIMS AND OBJECTIVE: The objectives were to describe and evaluate the structured medication questionnaire and to improve data handling of results from the Morisky four-item scale for patient compliance and Beliefs about Medicines Questionnaire-specific (BMQ-specific). METHODS: A questionnaire was developed with the purpose of being used when identifying medication errors and assessing patient compliance to and beliefs about medicines. RESULTS: A majority of the respondents (62%; CI 45-77%) had at least one medication error. Assuming that all items are equally important in the Morisky four-item scale we presented four alternative ways to create a unidimensional global scale. A two-dimensional global scale was also constructed. The results from the BMQ-specific were presented in different ways, all taking into account that the scale has ordered verbal categories: at the level addressing each specific question, at the sub-scales 'concern' and 'necessity' level and at the global level. CONCLUSIONS: The structured medication questionnaire can be used in daily practice as a tool to identify drug-related problems. The choice of how to use and present data from those scales in research depends on patient characteristics and how discriminating one would like the scales to be.
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| 21. |
- Vincents, Bjarne, et al.
(författare)
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The human protease inhibitor cystatin C is an activating cofactor for the streptococcal cysteine protease IdeS
- 2008
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Ingår i: Chemistry and Biology. - : Elsevier BV. - 1074-5521 .- 1879-1301. ; 15:9, s. 960-968
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Tidskriftsartikel (refereegranskat)abstract
- Human cystatin C is considered the physiologically most important inhibitor of endogenous papain-like cysteine proteases. We present here an unexpected function of cystatin C. Instead of acting as an inhibitor, cystatin C acts as a facultative, endogenous cofactor for the papain-like IgG-cleaving enzyme IdeS of the human pathogen Streptococcus pyogenes. IdeS activity is not dependent on cystatin C, but is significantly enhanced in the presence of cystatin C. We report a protease inhibitor that accelerates the activity of its putative target protease and a unique example of how a host protease inhibitor is "hijacked" by a bacterial protease to increase its activity. This finding has important implications for the view on protease-inhibitor interactions, and is relevant to consider in the therapeutic use of protease inhibitors.
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| 22. |
- Abdurahman, Samir, 1965-, et al.
(författare)
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Activity of the small modified amino acid alpha-hydroxy glycineamide on in vitro and in vivo human immunodeficiency virus type 1 capsid assembly and infectivity
- 2008
-
Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 52:10, s. 3737-3744
-
Tidskriftsartikel (refereegranskat)abstract
- Upon maturation of the human immunodeficiency virus type 1 (HIV-1) virion, proteolytic cleavage of the Gag precursor protein by the viral protease is followed by morphological changes of the capsid protein p24, which will ultimately transform the virus core from an immature spherical to a mature conical structure. Virion infectivity is critically dependent on the optimal semistability of the capsid cone structure. We have reported earlier that glycineamide (G-NH(2)), when added to the culture medium of infected cells, inhibits HIV-1 replication and that HIV-1 particles with aberrant core structures were formed. Here we show that it is not G-NH(2) itself but a metabolite thereof, alpha-hydroxy-glycineamide (alpha-HGA), that is responsible for the antiviral activity. We show that alpha-HGA inhibits the replication of clinical HIV-1 isolates with acquired resistance to reverse transcriptase and protease inhibitors but has no effect on the replication of any of 10 different RNA and DNA viruses. alpha-HGA affected the ability of the HIV-1 capsid protein to assemble into tubular or core structures in vitro and in vivo, probably by binding to the hinge region between the N- and C-terminal domains of the HIV-1 capsid protein as indicated by matrix-assisted laser desorption ionization-mass spectrometry results. As an antiviral compound, alpha-HGA has an unusually simple structure, a pronounced antiviral specificity, and a novel mechanism of antiviral action. As such, it might prove to be a lead compound for a new class of anti-HIV substances.
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| 23. |
- Jasir, Aftab, et al.
(författare)
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New antimicrobial peptide active against Gram-positive pathogens
- 2004
-
Ingår i: Indian Journal of Medical Research. - 0971-5916. ; 119:Suppl., s. 74-76
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Tidskriftsartikel (refereegranskat)abstract
- Background & objectives: Human and animal cystatins have been shown to inhibit the replication of certain viruses and bacteria, though it is not directly demonstrated that the effects are due to protease inhibitory capacity of the cystatins. We report antibacterial properties of a novel antimicrobial peptidyl derivative, (2S)-2-(N-alpha-benzyloxycarbonyl-arginyl-leucylamido)-1-(E)-cinnamoyla mido-3-methylbutane, structurally based upon the aminoterminal segment of the inhibitory centre of the human cysteine protease inhibitor, cystatin C. Methods: Clinical isolates of group A, B, C and G streptococci were collected. The antibacterial activity of Cystapep 1 derivative was tested by agar well diffusion method. Results: Cystapep 1, displayed antibacterial activity against several clinically important Gram-positive bacteria. It displayed minimal inhibitory and bactericidal concentrations of about 16 mug/ml for both Staphylococcus aureus and Streptococcus pyogenes. In radial agar diffusion assays, groups A, B, C and G streptococci as well as staphylococci were generally susceptible to the action of Cystapep 1, whereas pneumococci and enterococci were less susceptible. No activity against Gram-negative bacteria was observed. Interpretation & conclusion: Cystapep 1 also showed high activity against methicillin-resistant Staph. aureus (MRSA) and multi-antibiotic resistant coagulase negative staphylococci (CNS), suggesting its mechanism of action to be different from most currently used antibiotics.
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| 24. |
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| 25. |
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| 26. |
- Persson, Carl, et al.
(författare)
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Obalanserad medicinsk forskning
- 2001
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Ingår i: Läkartidningen. - 0023-7205. ; 98:34, s. 3580-3586
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Tidskriftsartikel (refereegranskat)
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| 27. |
- Pesonen, Erkki, et al.
(författare)
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Elevated infection parameters and infection symptoms predict an acute coronary event.
- 2008
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Ingår i: Therapeutic Advances in Cardiovascular Disease. - : SAGE Publications. - 1753-9447 .- 1753-9455. ; 2:6, s. 419-424
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The etiology and significance of flu-like symptoms often appearing before myocardial infarction should be clarified. METHODS: In a case-control study of 323 matched controls and a random sample of 110 out of 351 cases the presence of infection symptoms during the preceding four weeks before admission were asked and blood samples taken. RESULTS: Enterovirus (EV), herpes simplex virus (HSV), and Chlamydia pneumoniae IgA titers were significantly higher in cases than in controls (p<0.001, 0.008 and 0.046, respectively). Flu-like symptoms appeared significantly more often in patients than in controls the most common one being fatigue (p<0.001). In controls with fatigue, EV and HSV titers showed a trend to be higher (1.50 vs 1.45 and 4.29 vs 3.73) than in controls without fatigue but only HSV titers were statistically significantly higher (3.47 vs 3.96, p = 0.02). Even CRP and amyloid A concentrations (3.49 vs 2.08, p<0.0001 and 5.70 vs 3.77 mg/l, p = 0.003, respectively) as well as C4 (0.40 vs 0.44, p = 0.02) were higher in controls with fatigue. CONCLUSIONS: Odds ratios for a coronary event in a logistic regression model were 4.79 for fatigue and 2.72 for EV antibody levels in their fourth quartile. A linear-by-linear association test showed increasing number of single symptoms with higher EV titer quartiles (p = 0.004).
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| 28. |
- Roström, Björn, et al.
(författare)
-
Oligoclonal IgG bands synthesized in the central nervous system are present in rats with experimental autoimmune encephalomyelitis.
- 2004
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Ingår i: Acta Neurologica Scandinavica. - : Hindawi Limited. - 1600-0404 .- 0001-6314. ; 109:2, s. 106-112
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Oligoclonal bands (OBs) in electrophoresis of cerebrospinal fluid (CSF) are present in multiple sclerosis and here is investigated whether these also occur in experimental autoimmune encephalomyelitis (EAE). Material and methods: Experimental autoimmune encephalomyelitis was induced in 42 DA rats after immunization with rat spinal chord homogenate and the occurrence of OBs were detected by electrophoresis of both sera and CSF. The relationship between disease symptoms, antibody response against myelin basic protein (MBP), myelin oligodendrocyte glycoprotein (MOG) and appearance of OBs was studied. Results: Development of CSF-specific OB was found to occur, 6 weeks after immunization, in seven of 42 rats. OB was detected in rats with an antibody response against MBP, whereas as a role no such bands were present in rats with an antibody response against MOG. Initially severe disease symptoms were correlated to a concomitant intense oligoclonal antibody response. Conclusion: Cerebrospinal fluid-specific OB occurs in EAE. It is present in rats with an anti-MBP, but not in rats with an anti-MOG antibody response. A severe disease results in an intense oligoclonal antibody response, which might have an anti-inflammatory effect.
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| 29. |
- Medstrand, Patrik, et al.
(författare)
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Impact of transposable elements on the evolution of mammalian gene regulation.
- 2005
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Ingår i: Cytogenetic and Genome Research. - : S. Karger AG. - 1424-859X .- 1424-8581. ; 110:1-4, s. 342-352
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Forskningsöversikt (refereegranskat)abstract
- Transposable elements (TEs) are present in all organisms and nearly half of the human and mouse genome is derived from ancient transpositions. This fact alone suggests that TEs have played a major role in genome organization and evolution. Studies undertaken over the last two decades or so clearly show that TEs of various kinds have played an important role in organism evolution. Here we review the impact TEs have on the evolution Of gene regulation and gene function with an emphasis on humans. Understanding the mechanisms resulting in genomic change is central to our understanding of gene regulation, genetic disease and genome evolution. Full comprehension of these biological processes is not possible without an in depth knowledge of how TEs impact upon the genome.
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| 30. |
- Nasizadeh, Sima, et al.
(författare)
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Importance of polyamines in cell cycle kinetics as studied in a transgenic system.
- 2005
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 308:May 26, s. 254-264
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Tidskriftsartikel (refereegranskat)abstract
- Polyamines are organic cations, which are considered essential for normal cell cycle progression. This view is based on results from numerous studies using a variety of enzyme inhibitors or polyamine analogues interfering with either the metabolism or the physiological functions of the polyamines. However, the presence of non-specific effects may be hard to rule out in such studies. In the present study, we have for the first time used a transgenic cell system to analyze the importance of polyamines in cell growth. We have earlier shown that expression of trypanosomal ODC in an ODC-deficient variant of CHO cells (C55.7) supported growth of these otherwise polyamine auxotrophic cells. However, one of the transgenic cell lines grew much slower than the others. As shown in the present study, the level of ODC activity was much lower in these cells, and that was reflected in a reduction of cellular polyamine levels. Analysis of cell cycle kinetics revealed that reduction of growth was correlated to prolongation of the G(1), S, and G(2) + M phases in the cells. Providing exogenous putrescine to the cells resulted in a normalization of polyamine levels as well as cell cycle kinetics indicating a causal relationship.
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| 31. |
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| 32. |
- Palkovicova, K., et al.
(författare)
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A monoclonal antibody specific for a unique biomarker, virenose, in a lipopolysaccharide of Coxiella burnetii
- 2009
-
Ingår i: Clinical Microbiology and Infection. - : Elsevier. - 1198-743X .- 1469-0691. ; 15 Suppl 2, s. 183-4
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Tidskriftsartikel (refereegranskat)abstract
- Q fever is a zoonotic disease caused by Coxiella burnetii. Easy aerosol dissemination, strong environmental persistence and high infectivity make the bacterium a serious threat for humans and animals. A rapid, sensitive and specific test for the infectious agent is still a challenge in the field. C. burnetii expresses a spectrum of amphophilic macromolecules on its surface. Among them, a lipopolysaccharide (LPS) is of particular biological, immunological and medical significance [1]. Upon serial laboratory passages in yolk sacs of embryonated hen eggs, C.
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| 33. |
- Andersson, Anna, et al.
(författare)
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Lactate contributes to ammonia-mediated astroglial dysfunction during hyperammonemia.
- 2009
-
Ingår i: Neurochemical research. - : Springer Science and Business Media LLC. - 1573-6903 .- 0364-3190. ; 34:3, s. 556-65
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Tidskriftsartikel (refereegranskat)abstract
- Even though ammonia is considered to underlie nervous system symptoms of dysfunction during hyperammonemia, lactate, which increases as a metabolic consequence of high ammonia levels, might also be a contributing factor. The data presented here show that NH4Cl (5 mM) mediates astroglial cell swelling, and that treatment with NH4Cl or lactate (25 mM) causes rearrangements of actin filaments and reduces astroglial glutamate uptake capacity. Co-application with BaCl2, which blocks astroglial uptake of NH4+, prevents NH4Cl-mediated cell swelling and rearrangement of actin filaments, but does not reduce NH4Cl-induced glutamate uptake capacity inhibition. Neither NH4Cl nor lactate affected glutamate uptake or protein expression in microglial cultures, indicating that astroglial cells are more susceptible to the neurotoxic affects of ammonia. Our results suggest that ammonium underlies brain edema, but that lactate can contribute to some of the cellular dysfunctions associated with elevated cerebral levels of ammonia.
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| 34. |
- Andersson, Daniel, et al.
(författare)
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Partial depletion of dopamine in substantia nigra impairs motor performance without altering striatal dopamine neurotransmission
- 2006
-
Ingår i: European Journal of Neuroscience. - : Wiley. - 0953-816X .- 1460-9568. ; 24:2, s. 617-624
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Tidskriftsartikel (refereegranskat)abstract
- Previous data indicate that the release of somatodendritic dopamine in substantia nigra influences motor activity and coordination, but the relative importance of somatodendritic dopamine release vs. terminal striatal dopamine release remains to be determined. We utilized simultaneous measurement of dopamine neurotransmission by microdialysis and motor performance assessment by rotarod test to investigate the effects of local dopamine depletion in rats. The vesicular monoamine transporter inhibitor tetrabenazine (100 µm) was administered locally in substantia nigra as well as in striatum. Nigral tetrabenazine administration decreased nigral dopamine dialysate concentrations to 7% of baseline and whole-tissue dopamine content by 60%. Nigral dopamine depletion was associated with a reduction in motor performance to 73 ± 6% of pretreatment value, but did not alter dialysate dopamine concentrations in the ipsilateral striatum. Striatal tetrabenazine administration decreased striatal dopamine dialysate concentrations to 5% of baseline and doubled the somatodendritic dopamine response to motor activity, but it was not associated with changes in motor performance or dopamine content in striatal tissue. Simultaneous treatment of substantia nigra and striatum reduced motor performance to 58 ± 5% of the pretreatment value. The results of this study indicate that partial depletion of nigral dopamine stores can significantly impair motor functions, and that increased nigral dopamine release can counteract minor impairments of striatal dopamine transmission.
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| 35. |
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| 36. |
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| 37. |
- Carlsson, Marcus, et al.
(författare)
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Atrioventricular plane displacement is the major contributor to left ventricular pumping in healthy adults, athletes, and patients with dilated cardiomyopathy
- 2007
-
Ingår i: American Journal of Physiology: Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 292:3, s. 1452-1459
-
Tidskriftsartikel (refereegranskat)abstract
- Previous studies using echocardiography in healthy subjects have reported conflicting data regarding the percentage of the stroke volume ( SV) of the left ventricle ( LV) resulting from longitudinal and radial function, respectively. Therefore, the aim was to quantify the percentage of SV explained by longitudinal atrioventricular plane displacement ( AVPD) in controls, athletes, and patients with decreased LV function due to dilated cardiomyopathy ( DCM). Twelve healthy subjects, 12 elite triathletes, and 12 patients with DCM and ejection fraction below 30% were examined by cine magnetic resonance imaging. AVPD and SV were measured in long- and short- axis images, respectively. The percentage of the SV explained by longitudinal function ( SVAVPD%) was calculated as the mean epicardial area of the largest short- axis slices in end diastole multiplied by the AVPD and divided by the SV. SV was higher in athletes [ 140 +/- 4 ml ( mean +/- SE), P = 0.009] and lower in patients ( 72 +/- 7 ml, P < 0.001) when compared with controls ( 116 +/- 6 ml). AVPD was similar in athletes ( 17 +/- 1 mm, P = 0.45) and lower in patients ( 7 +/- 1 mm, P = 0.001) when compared with controls ( 16 +/- 0 mm). SVAVPD% was similar both in athletes ( 57 +/- 2%, P = 0.51) and in patients ( 67 +/- 4%, P = 0.24) when compared with controls ( 60 +/- 2%). In conclusion, longitudinal AVPD is the primary contributor to LV pumping and accounts for similar to 60% of the SV. Although AVPD is less than half in patients with DCM when compared with controls and athletes, the contribution of AVPD to LV function is maintained, which can be explained by the larger short- axis area in DCM.
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| 38. |
- Decker, Ralph, 1968, et al.
(författare)
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Different thresholds of metabolic GH effects in prepubertal children
- 2009
-
Ingår i: Hormone Research.
-
Konferensbidrag (refereegranskat)abstract
- Context: In addition to growth hormone (GH) effects to promote linear growth in children, GH also has substantial effects on insulin sensitivity, lipolysis, lipids, and body composition. A dissociation between anabolic and lipolytic GH effects has been suggested. Objective: The objective of the present study was to further investigate dissociated GH effects by calculating the GH doses to attain half of a given metabolic effect, the effective dose 50% (ED50%). Hypothesis: The hypothesis was that there are dose-dependent thresholds in different variables reflecting metabolism. Design: A randomized, prospective, multicentre trial was performed for a 2 years period, with two treatment regimens in short prepubertal GHD and ISS children a) individualized GH dose with six different dose groups ranging 17-100 g/kg/day (n=87) and b) fixed GH dose of 43 g/kg/day (n=41). Results: Contrary to changes in fat mass, leptin, lipids and skinfold measurements, there was evidence for different thresholds in metabolic variables for a given GH dose when performing ANOVA, p<0.001. was calculated as the difference between 2 years and start of GH treatment. Besides height (SDS), growth related variables like weight SDS and BMI (kg/m ); measures of body composition such as fat-free mass (FFM) (kg), FFM index (FFMI) (kg/m ), waist (cm), hip (cm); as well as biochemical markers like IGF-1 (SDS), IGFBP-3 (SDS); insulin (mU/L) showed dose-dependency with different ED50% levels. Conclusions: Differences of the ED50% on metabolic variables were seen in-between different GH dose spans. Thus we propose that there are different thresholds in GH effects on variables reflecting different metabolic aspects, suggesting muscle tissue being more sensitive than linear growth, GH induced insulin resistance, the rise in IGF-1 and the increase in hip circumference as a measure of 3-dimensional body growth.
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| 39. |
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| 40. |
- Ekström, Jörgen, 1944, et al.
(författare)
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Neural- and Hormonal-induced Protein Synthesis and Mitotic Activity in the Rat Parotid Gland and the Dependence on NO-generation
- 2007
-
Ingår i: Journal of Oral Biosciences. - : Elsevier. - 1349-0079 .- 1880-3865. ; 49:1, s. 31-38
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Tidskriftsartikel (refereegranskat)abstract
- Nitric oxide (NO) is a likely parasympathetic nonadrenergic, noncholinergic transmitter in parotid glands, since parasympathetic nerves contain NO-synthase. Parasympathetic stimulation (30 min, atropine + phentolamine + propranolol) increased the protein synthesis ([3H] leucine uptake) by 142% (10 Hz) and 200% (40 Hz). Surprisingly, neither the neuronal type NO-synthase inhibitor N-PLA, nor the unspecific inhibitor L-NAME reduced the response. Moreover, the parasympathetic nonadrenergic, noncholinergic (40 Hz, 30 min)-evoked increase (65%) in mitotic activity ([3H] thymidine uptake) was unaffected by the NO-synthase inhibitors. Sympathetic nerves lack NO-synthase, yet inhibition of NO-generation reduced the β-adrenoceptor mediated response to sympathetic stimulation. Whereas the protein synthesis increased by 192% to stimulation (50 Hz, 1s every tenth s for 30 min) under just α-adrenoceptor blockade, the response was more than halved in the presence of N-PLA to 86%) or L-NAME to 91%). Furthermore, the β-adrenoceptor mediated increase in mitotic activity 122%) to sympathetic stimulation 20 Hz, 4 min every fifth min for 30 min), under α-adrenoceptor blockade, was reduced to 49% N-PLA) and 47% (L-NAME). Pentagastrin (20 µg/kg, I. V. infused for one h) increased the protein synthesis by 17%. N-PLA prevented this increase but did not affect the basal protein, while cholecystokinin receptor blockers reduced both the basal protein synthesis (by 20%), and the pentagastrin-induced increase. Thus, implying that strong rather than weak stimuli of the cholecystokinin receptors activate neuronal type NO-synthase. Despite being of the neuronal type, the NO-synthase generating NO in response to stimulation of β-adrenoceptors or cholecystokinin receptors was probably of parenchymal origin.
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| 41. |
- Ericson, Mia, 1970, et al.
(författare)
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Ethanol elevates accumbal dopamine levels via indirect activation of ventral tegmental nicotinic acetylcholine receptors.
- 2003
-
Ingår i: European journal of pharmacology. - 0014-2999. ; 467:1-3, s. 85-93
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Tidskriftsartikel (refereegranskat)abstract
- It was previously demonstrated that the central nicotinic acetylcholine receptor antagonist mecamylamine perfused in the ventral tegmental area (VTA) counteracts the elevation of extracellular dopamine levels in the nucleus accumbens after systemic ethanol, as measured by in vivo microdialysis. In the present study we investigated the effect of different concentrations of ethanol perfused locally in the VTA or in the nucleus accumbens on extracellular accumbal dopamine levels. Ethanol (10-1000 mM) perfused in the VTA did not influence dopamine output in the nucleus accumbens. However, ethanol (300 mM) perfused in the nucleus accumbens increased accumbal dopamine levels to approximately the same extent (30%) as observed after systemic ethanol, whereas ethanol (1000 mM) decreased the dopamine output by approximately 50%. Next, the hypothesis that endogenous acetylcholine is required for the increased accumbal dopamine levels after ethanol was challenged. It was shown that in animals pre-treated with vesamicol, a potent inhibitor of vesicular acetylcholine storage, ethanol (300 mM) in the nucleus accumbens failed to elevate extracellular accumbal dopamine levels. Similarly, in animals perfused with mecamylamine in the VTA, but not in the nucleus accumbens, ethanol in the nucleus accumbens (300 mM) failed to increase accumbal dopamine levels. However, whereas dihydro-beta-erythroidine (antagonist for the nicotinic receptor subtype alpha4beta2) perfused in the VTA prevented the increase in accumbal dopamine after systemic nicotine, the antagonist was unable to prevent the dopamine elevating effects of ethanol. Finally, to investigate whether mecamylamine exerts its antagonizing effect of ethanol induced accumbal dopamine levels through an interaction with the NMDA receptor MK-801, the effects of the prototypic NMDA receptor antagonist were examined and compared to those of mecamylamine. After perfusion in the VTA, MK-801 enhanced accumbal dopamine levels by itself but did not antagonize the enhancing effect of ethanol. The present set of experiments indicate that the mesolimbic dopamine activating effects of ethanol may be due to an indirect rather than direct activation of ventral tegmental nicotinic acetylcholine receptors of a subtype composition different from the alpha4beta2. Furthermore, it is argued that the primary site of action of ethanol in its accumbal dopamine elevating effect may be located to the nucleus accumbens or nearby regions.
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| 42. |
- Ericson, Mia, 1970, et al.
(författare)
-
Nicotinic acetylcholine receptors in the anterior, but not posterior, ventral tegmental area mediate ethanol-induced elevation of accumbal dopamine levels.
- 2008
-
Ingår i: The Journal of pharmacology and experimental therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103 .- 0022-3565. ; 326:1, s. 76-82
-
Tidskriftsartikel (refereegranskat)abstract
- Ethanol-induced elevations of accumbal dopamine levels have been linked to the reinforcing properties of the drug. However, it has not yet been demonstrated where the primary point of action of ethanol is in the mesolimbic dopamine system, and there appear to be conflicting findings depending on methodology (electrophysiology, microdialysis, or intracranial self-administration). We have suggested that ethanol acts in the nucleus accumbens (nAc), where it activates a neuronal loop involving ventral tegmental nicotinic acetylcholine receptors (nAChRs) to elevate dopamine levels in the nAc. Application of ethanol in the nAc results in elevated dopamine levels in the same brain region, whereas administration in the anterior ventral tegmental area (VTA) fails to influence dopamine output. In the present study, we were able to repeat these findings. In addition, application of ethanol in the posterior VTA also failed to influence nAc dopamine levels. Perfusion of the nAChR antagonist mecamylamine in the anterior VTA completely blocked the elevation of accumbal dopamine levels observed after ethanol perfusion in nAc, whereas mecamylamine in the posterior VTA had no effect. To detect a possible influence on phasic dopamine release, the dopamine transporter inhibitor nomifensine was included in the accumbal perfusate. In addition, under these conditions, ethanol in the anterior or posterior VTA failed to influence dopamine release in the nAc. These results support previous suggestions of distinct functions of the anterior and posterior VTA and give further evidence for our hypothesis of a nAc-anterior VTA-nAc neuronal circuitry involved in the dopamine-activating effects of ethanol.
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| 43. |
- Friberg, P. Anders, 1976, et al.
(författare)
-
Apoptotic effects of a progesterone receptor antagonist on rat granulosa cells are not mediated via reduced protein isoprenylation.
- 2007
-
Ingår i: Molecular reproduction and development. - : Wiley. - 1040-452X .- 1098-2795. ; 74:10, s. 1317-26
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Tidskriftsartikel (refereegranskat)abstract
- Progesterone is a survival factor in rat periovulatory granulosa cells. The mechanisms involved are unclear but progesterone receptor (PGR) antagonists have been shown to inhibit cholesterol synthesis and induce apoptosis. Furthermore, reports suggest that statins induce apoptosis by inhibition of protein isoprenylation. Statins inhibit the rate-limiting step of the cholesterol synthesis, thereby reducing availability of intermediates used for the post-translational isoprenylation process. It has been suggested that PGR antagonists in a similar manner induce apoptosis by decreasing cholesterol synthesis and thereby protein isoprenylation. In this study we hypothesized that the mechanism by which the nuclear PGR antagonist Org 31,710 induces apoptosis in rat periovulatory granulosa cells, is by decreasing cholesterol synthesis and thereby general cell protein isoprenylation. Incubation of isolated granulosa cells with Org 31,710 or simvastatin for 22 hr resulted in increased apoptosis and reduced cholesterol synthesis. However, simvastatin caused a substantial inhibition of cholesterol synthesis after 6 hr in culture without inducing apoptosis. In contrast, Org 31,710 had only a modest effect on cholesterol synthesis after 6 hr while it significantly induced apoptosis. Addition of isoprenylation substrates partially reversed apoptosis induced by simvastatin and to a lesser extent apoptosis induced by Org 31,710. In addition, and in contrast to Org 31,710, simvastatin caused a decrease in isoprenylation of a selected isoprenylation marker protein, the Ras-related protein RAB11. In conclusion, we demonstrate that the PGR antagonist inhibits cholesterol synthesis in granulosa cells but reduced protein isoprenylation is not the mediating mechanism of increased apoptosis as previously hypothesized.
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| 44. |
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| 45. |
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| 46. |
- Gunnarsson, Lina-Maria, 1977, et al.
(författare)
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Pharmaceutical industry effluent diluted 1:500 affects global gene expression, cytochrome P4501A activity and plasma phosphate in fish
- 2009
-
Ingår i: Environmental Toxicology and Chemistry. - : Society of Environmental Toxicology and Chemistry (SETAC). - 0730-7268 .- 1552-8618. ; 28:12, s. 2639-2647
-
Tidskriftsartikel (refereegranskat)abstract
- Patancheru, near Hyderabad, India, is a major production site for the global bulk drug market. Approximately 90 manufacturers send their wastewater to a common treatment plant in Patancheru. Extraordinary high levels of a wide range of pharmaceuticals have recently been demonstrated in the treated effluent. As little as 0.2% of this effluent can strongly reduce the growth rate of tadpoles, but the underlying mechanisms of toxicity are not known. To begin addressing how the effluent affects aquatic vertebrates, rainbow trout (Oncorhynchus mykiss) were exposed to 0.2% effluent for five days. Several physiological endpoints, together with effects on global hepatic gene expression patterns, were analyzed. The exposed fish showed both an induction of hepatic cytochrome P450 1A (CYP1A) gene expression, as well as enzyme activity. Clinical blood chemistry analyses revealed an increase in plasma phosphate levels, which in humans indicates impaired kidney function. Several oxidative stress-related genes were induced in the livers; however, no significant changes in antioxidant enzyme activities or in the hepatic glutathione levels were found. Furthermore, estrogen-regulated genes were slightly up-regulated following exposure, and moderate levels of estriol were detected in the effluent. The present study identifies changes in gene expression triggered by exposure to a high dilution of the effluent, supporting the hypothesis that these fish are responding to chemical exposure. The pattern of regulated genes may contribute to the identification of mechanisms of sub-lethal toxicity, as well as illuminate possible causative agents.
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| 47. |
- Götrick, Bengt, et al.
(författare)
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Effects of amphetamine on salivary secretion
- 2009
-
Ingår i: European Journal of Oral Sciences. - : Wiley InterScience. - 0909-8836 .- 1600-0722. ; 117:3, s. 218-223
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Tidskriftsartikel (refereegranskat)abstract
- Amphetamine induces xerogenic effects, but its mechanism of action and xerogenic potency are unknown. In the current in vivo study on the rat parotid gland, the effects of amphetamine on reflex-evoked and acetylcholine-evoked salivation were examined in the absence and presence of adrenergic and dopaminergic antagonists. Under anaesthesia, amphetamine increased the secretion of salivary fluid and the amount of protein therein in response to acetylcholine. Phentolamine abolished the increase in salivary flow and had no effect on the salivary protein concentration, whereas propranolol only reduced the salivary protein concentration. Reflex activation of the secretion evoked a well-maintained level of secretion that was reduced by amphetamine [50% inhibitory dose (ID50) 1.9 ± 0.1 mg kg−1 intravenously); the salivary protein concentration was increased in the presence of amphetamine. Phentolamine and haloperidol reduced the amphetamine-inhibitory effect on the reflex-evoked fluid response, whereas propranolol had no effect on the fluid response. The xerogenic effect of amphetamine is mainly exerted by central mechanisms involving α-adrenoceptors, while, indirectly, amphetamine causes secretion of protein by inducing the release of noradrenaline from glandular nerve terminals.
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| 48. |
- Götrick, Bengt, et al.
(författare)
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The xerogenic potency and mechanism of action of tramadol inhibition of salivary secretion in rats.
- 2004
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Ingår i: Archives of oral biology. - : Elsevier BV. - 0003-9969 .- 1879-1506. ; 49:12, s. 969-73
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Tidskriftsartikel (refereegranskat)abstract
- Tramadol is a centrally acting analgesic with weak opioid agonist properties, which also has monoaminergic activity, exerted via inhibition of neuronal uptake of serotonin and norepinephrine. Tramadol is generally well tolerated and the most common adverse events are nausea, dizziness, drowsiness, sweating, vomiting and dry mouth. Currently it was examined by which principal mechanism tramadol induces oral dryness. The effects of intravenous administration (+/-)-tramadol were studied in rats on the flow of saliva in response to a peripheral cholinergic stimulus or to reflex activation involving the relay of impulses in the central nervous system. In pentobarbitone-anaesthetized rats, the salivary secretion to acetylcholine (0.1-10 micromol/kg IV) was increased by up to 110% by tramadol (1-5 mg/kg IV) and the protein concentration therein by up to 400%. The administration alpha- and beta-adrenoceptor antagonists resulted in almost identical acetylcholine-evoked responses as in the absence of tramadol. The secretory response to the application of citric acid on the tongue of the rat was reduced by 38% and by 64%, respectively, at 5 and 10 mg/kg IV of tramadol (p < 0.05-0.01). Thus, tramadol exerts its principal xerogenic effect by activating inhibitory pathways in the central nervous system and has no anticholinergic effect on the salivary glands at dosages that may be clinically relevant. Furthermore, the tramadol-induced increase of the acetylcholine-evoked secretion occurred at a glandular level and depended most likely on a release of noradrenaline from glandular nerve terminals.
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| 49. |
- Hawes, Jessica, et al.
(författare)
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Galanin Protects Against Behavioral and Neurochemical Correlates of Opiate Reward
- 2008
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Ingår i: Neuropsychopharmacology. - : Springer Science and Business Media LLC. - 0893-133X .- 1740-634X. ; 33:8, s. 1864-1873
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms underlying responses to drugs of abuse have been widely investigated; however, less is known about pathways normally protective against the development of drug reinforcement. These pathways are also important since they may regulate individual differences in vulnerability to addiction. The neuropeptide galanin and its binding sites are expressed in brain areas important for drug reward. Previous studies have shown that centrally infused galanin attenuates morphine place preference and peripheral injection of galnon, a galanin agonist, decreases opiate withdrawal signs. The current studies in galanin knockout (GKO) mice examined the hypothesis that galanin is an endogenous negative regulator of opiate reward and identified downstream signaling pathways regulated by galanin. We show that GKO mice demonstrate increased locomotor activation following morphine administration, which is inhibited by acute administration of galnon. GKO mice also show enhanced morphine place preference, supporting the idea that galanin normally antagonizes opiate reward. In addition, morphine-induced ERK1/2 phosphorylation was increased in the VTA of both wild-type and GKO mice, but only the GKO mice showed increases in ERK1/2 and CREB phosphorylation in the amygdala or nucleus accumbens. Furthermore, a single systemic injection of galnon in GKO mice was sufficient to reverse some of the biochemical changes brought about by morphine administration. These data suggest that galanin normally attenuates behavioral and neurochemical effects of opiates; thus, galanin agonists may represent a new class of therapeutic targets for opiate addiction.
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| 50. |
- Hedner, Thomas, 1949, et al.
(författare)
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Valuable lessons from VALUE.
- 2004
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Ingår i: Blood pressure. - Stockholm : Taylor & Francis. - 0803-7051. ; 13:4, s. 196-7
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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