| 11. |
- Kugelberg, Fredrik, 1974-, et al.
(författare)
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In vivo steady-state pharmacokinetic outcome following clinical and toxic doses of racemic citalopram to rats
- 2001
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Ingår i: British Journal of Pharmacology. - : Wiley. - 0007-1188 .- 1476-5381. ; 132:8, s. 1683-1690
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Tidskriftsartikel (refereegranskat)abstract
- The thymoleptic drug citalopram (CIT) belongs to the selective serotonin reuptake inhibitors (SSRIs) and is today extensively used in psychiatry. Further clarification of the enantiomer-selective distribution of racemic CIT in both clinical and toxic doses is highly warranted.By a steady-state in vivo paradigm, rats underwent chronic systemic exposure for 10 days by using osmotic pumps and the total as well as the individual distributions of the S- and R-enantiomers of CIT, and its metabolites in serum and two different brain regions, were analysed.In serum, the S/R ratios in the groups treated with 10, 20, or 100 mg kg−1 day−1 were 0.94, 0.83, and 0.34, respectively. The ratios were almost the same in the brain regions.In the group treated with 100 mg kg−1 day−1, the serum and brain total CIT levels were found to be 20 times and 6 – 8 times higher than in the rats treated with 10 or 20 mg kg−1 day−1, respectively. In all groups, the CIT levels were higher in brain tissue as compared to serum.In a spontaneous open-field behavioural test, a correlation between clinical and toxic drug concentrations was observed.In conclusion, the R-enantiomer was present in an increased proportion compared with the S-enantiomer when higher steady-state CIT concentration was prevailing. This is of particular interest, since the S-enantiomer is responsible for the inhibition of serotonin reuptake in vitro. The present data may be of importance, as full understanding on where different racemic or enantiomeric drug effects of CIT and its main metabolites are unravelled.
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| 12. |
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| 13. |
- Li, Xiang, et al.
(författare)
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Interleukin-10 mediates the protective effect of Linomide by reducing CXC chemokine production in endotoxin-induced liver injury
- 2004
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Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 143:7, s. 865-871
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Tidskriftsartikel (refereegranskat)abstract
- 1 The immunomodulator Linomide has been shown to protect against septic liver injury by reducing hepatic accumulation of leukocytes although the detailed anti-inflammatory mechanisms remain elusive. This study examined the effect of Linomide on the production of CXC chemokines, including macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC) and interleukin-10 (IL-10) in lipopolysaccharide (LPS)/D-galactosamine (Gal)-induced liver injury in mice. 2 It was found that pretreatment with 300 mg kg(-1) of Linomide markedly Suppressed leukocyte recruitment, perfusion failure, and hepatocellular damage and apoptosis in the liver of endotoxemic mice. 3 Administration of Linomide inhibited endotoxin-induced gene expression of MIP-2 and KC and significantly reduced the hepatic production of MIP-2 and KC by 63 and 80%, respectively. Moreover, it was found that Linomide increased the liver content of IL-10 by more than three-fold in endotoxemic mice. 4 The protective effect of Linomide against endotoxin-induced inflammation and liver injury was abolished in IL-10-deficient mice, suggesting that the beneficial effect of Linomide is dependent on the function of IL-10. 5 Taken together, these novel findings suggest that the protective effect of Linomide is mediated via local upregulation of IL-10, which in turn decreases the generation of CXC chemokines and pathological recruitment of leukocytes in the liver of endotoxemic mice.
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| 14. |
- Li, Xiang, et al.
(författare)
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Lymphocyte function antigen-1 mediates leukocyte adhesion and subsequent liver damage in endotoxemic mice
- 2004
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Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 141:4, s. 709-716
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Tidskriftsartikel (refereegranskat)abstract
- 1 Sepsis is associated with leukocyte activation and recruitment in the liver. We investigated the role of lymphocyte function antigen-1 (LFA-1) in endotoxin-induced leukocyte-endothelium interactions, microvascular perfusion failure, hepatocellular injury and apoptosis in the liver by use of gene-targeted mice, blocking antibodies and a synthetic inhibitor of LFA-1 (LFA703). For this purpose, mice were challenged with lipopolysaccharide (LPS)+D-galactosamine (Gal), and intravital microscopy of the liver microcirculation was conducted 6 h later. 2 The number of Firmly adherent leukocytes in response to LPS/Gal was reduced by 48% in LFA-1-deficient mice. Moreover, endotoxin-induced increases of apoptosis and enzyme markers of hepatocellular injury were decreased by 64 and 69-90%, respectively, in LFA-1-deficient mice. Furthermore, sinusoidal perfusion was improved in endotoxemic mice lacking LFA-1. 3 A similar protective pattern was observed in endotoxemic mice pretreated with an antibody against LFA-1. Thus, immunoneutralization of LFA-1 reduced endotoxin-induced leukocyte adhesion by 55%, liver enzymes by 64-66% and apoptosis by 42%, in addition to the preservation of microvascular perfusion. 4 Administration of a novel statin-derived inhibitor of LFA-1, LFA703, significantly decreased leukocyte adhesion (more than 56%) and the subsequent liver injury in endotoxemic mice. 5 Thus, this study demonstrates a pivotal role of LFA-1 in supporting leukocyte adhesion in the liver. Moreover, interference with LFA-1-mediated leukocyte adhesion protects against endotoxemic liver damage, and may constitute a potential therapeutic strategy in sepsis.
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| 15. |
- Ling, Maria K, et al.
(författare)
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The melanocortin receptor subtypes in chicken have high preference to ACTH-derived peptides
- 2004
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Ingår i: British Journal of Pharmacology. - : Wiley. - 0007-1188 .- 1476-5381. ; 143:5, s. 626-637
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Tidskriftsartikel (refereegranskat)abstract
- 1 Melanocortin (MC) receptors are widely distributed throughout the body of chicken, like in mammals, and participate in a wide range of physiological functions. 2 To clarify the pharmacological impact of ligands acting in the MC system, we expressed the chicken MC1, MC2, MC3, MC4 and MC5 (cMC1-5) receptors in eukaryotic cells and performed comprehensive pharmacological characterization of the potency of endogenous and synthetic melanocortin peptides. 3 Remarkably, the cMC receptors displayed high affinity for ACTH-derived peptides and in general low affinity for alpha-MSH. It is evident that not only the cMC2 receptor but also the other cMC receptors interact with ACTH-derived peptide through an epitope beyond the sequence of alpha-MSH. 4 The synthetic ligand MTII was found to be a potent agonist whereas HS024 was a potent antagonist at the cMC4 receptor, indicating that these ligands are suitable for physiological studies in chicken. 5 We also show the presence of prohormone convertase 1 (PC1) and PC2 genes in chicken, and that these peptides are coexpressed with proopiomelanocortin (POMC) in various tissues.
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| 16. |
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| 17. |
- Lördal, Mikael, et al.
(författare)
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A novel tachykinin NK2 receptor antagonist prevents motility-stimulating effects of neurokinin A in small intestine
- 2001
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Ingår i: British Journal of Pharmacology. - 0007-1188 .- 1476-5381. ; 134:1, s. 215-223
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Tidskriftsartikel (refereegranskat)abstract
- 1. MEN 11420 (nepadutant) is a potent, selective and competitive antagonist of tachykinin NK2 receptors. 2. The objective of the present study was to assess the capability of the drug to antagonize the stimulatory effects of neurokinin A (NKA) on gastrointestinal motility, as well as to change the fasting migrating motor complex (MMC). 3. Thirty-four male volunteers were randomized to treatment with either placebo or MEN 11420 in a double-blinded manner. Effects of MEN 11420 (8 mg intravenously) were evaluated as changes in phases I, II and III of MMC, as well as contraction frequency, amplitude and motility index during baseline conditions and during stimulation of motility using NKA (25 pmol kg-1 min-1 intravenously). 4. NKA preceded by placebo increased the fraction of time occupied by phase II, increased contraction frequency, amplitude and motility index. 5. MEN 11420 effectively antagonized the motility-stimulating effects of NKA. MEN 11420 reduced the phase II-stimulating effect of NKA. In addition, the stimulatory effect of NKA on contraction frequency and amplitude, as well as motility index were inhibited by MEN 11420. MEN 11420 did not affect the characteristics of MMC during saline infusion. 6. Plasma levels of MEN 11420 peaked during the first hour after infusion and decreased to less than half during the first 2 h. 7. In conclusion, intravenous MEN 11420 effectively inhibited NKA-stimulated, but not basal gastrointestinal motility, and was well tolerated by all subjects.
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| 18. |
- Malmsjö, Malin, et al.
(författare)
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The stable pyrimidines UDPbetaS and UTPgammaS discriminate between the P2 receptors that mediate vascular contraction and relaxation of the rat mesenteric artery
- 2000
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Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 131:1, s. 51-56
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Tidskriftsartikel (refereegranskat)abstract
- The contractile and relaxant effects of the different P2 receptors were characterized in the rat isolated mesenteric artery by use of extracellular nucleotides, including the stable pyrimidines uridine 5'-O-thiodiphosphate (UDPbetaS) and uridine 5'-O-3-thiotriphosphate (UTPgammaS). The selective P2X receptor agonist, alphabeta-methylene-adenosine triphosphate (alphabeta-MeATP) stimulated a potent (pEC(50)=6.0) but relatively weak contraction (E:(max)=57% of 60 mM K(+)). The contractile concentration-response curve of adenosine triphosphate (ATP) was biphasic when added in single concentrations. The first part of the response could be desensitized by alphabeta-MeATP, indicating involvement of P2X receptors, while the second part might be mediated by P2Y receptors. The contractile P2Y receptors were further characterized after P2X receptor desensitization with 10 microM alphabeta-MeATP. Uridine diphosphate (UDP), uridine triphosphate (UTP) and ATP stimulated contraction only in high concentrations (1 - 10 mM). The selective P2Y(6) agonist, UDPbetaS, and the P2Y(2)/P2Y(4)-receptor agonists UTPgammaS and adenosine 5'-O-3-thiotriphosphate (ATPgammaS) were considerably more potent and efficacious (E:(max) approximately 250% of 60 mM K(+)). Adenosine 5'-O-thiodiphosphate (ADPbetaS) was inactive, excluding contractile P2Y(1) receptors. After precontraction with 1 microM noradrenaline, UTP, ADP and ATP induced relaxations with similar potencies (pEC(50) approximately 5.0). UTPgammaS, ADPbetaS and ATPgammaS were approximately one log unit more potent indicating the presence of endothelial P2Y(1) and P2Y(2)/P2Y(4) receptors. The P2Y(6) receptor agonist, UDPbetaS, had no effect. UDPbetaS and UTPgammaS are useful tools when studying P2 receptors in tissue preparations with ectonucleotidase activity. Contractile responses can be elicited by stimulation of P2Y(6) and, slightly less potently, P2Y(2)/P2Y(4) receptors. The P2X response was relatively weak, and there was no P2Y(1) response. Stimulation of P2Y(1) and P2Y(2)/P2Y(4) receptors elicited relaxation, while P2Y(6) did not contribute.
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| 19. |
- Mizusawa, Hiroya, et al.
(författare)
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Enhancement of apomorphine-induced penile erection in the rat by a selective alpha(1D)-adrenoceptor antagonist.
- 2002
-
Ingår i: British Journal of Pharmacology. - : Wiley. - 0007-1188 .- 1476-5381. ; 136:5, s. 701-8
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Tidskriftsartikel (refereegranskat)abstract
- 1. Effects of A-322312 (alpha(1B)-adrenoceptor (AR) antagonist), A-119637 (alpha(1D)-AR antagonist), prazosin (non-selective alpha(1)-AR antagonist), and yohimbine (alpha(2)-AR antagonist) were studied in rat corpus cavernosum (CC) and cavernous artery (Acc) preparations. Effects of intracavernous (i.c.) or intraperitoneal (i.p.) administration of alpha(1)-AR antagonists on apomorphine-induced erections were investigated. 2. A-119637 attenuated electrically induced contractions in isolated CC (-logIC(50); 8.12+/-0.15), and relaxed noradrenaline (NA)-contracted preparations by more than 90% at 10(-7) M. At the same concentration, the -logEC(50) value for NA in Acc was altered from 6.79+/-0.07 to 4.86+/-0.13. In the CC and Acc, prazosin similarly inhibited contractile responses. 3. Inhibitory effects of A-322312 (10(-7) M) in electrically activated CC were 32.3+/-5.1%, whereas no effect on concentration-response curves for NA was observed in the Acc. Yohimbine (10(-8) M and 10(-7) M), enhanced electrically-induced contractions in isolated CC by 20 to 50%. At 10(-6) M, inhibitory effects of yohimbine were obtained. 4. A-119637 (0.3 micromol kg(-1), i.p.) tripled the number of erections, and produced a 6 fold increase in the duration of apomorphine-induced erectile responses. A-322312, prazosin, or yohimbine did not enhance erections induced by apomorphine. None of the alpha(1)-AR antagonists significantly increased ICP upon i.c. administration. Decreases in blood pressure were seen with A-119637 and prazosin. 5. The present findings show that there is a functional predominance of the alpha(1D)-AR subtype in the rat erectile tissue, and that blockade of this receptor facilitates rat penile erection induced by a suboptimal dose of apomorphine.
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| 20. |
- Mizusawa, Hiroya, et al.
(författare)
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Morphological and functional in vitro and in vivo characterization of the mouse corpus cavernosum.
- 2001
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Ingår i: British Journal of Pharmacology. - : John Wiley & Sons. - 0007-1188 .- 1476-5381. ; 132:6, s. 1333-1341
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Tidskriftsartikel (refereegranskat)abstract
- 1. In normal mice, the distribution of adrenergic, cholinergic, some peptidergic, and neuronal nitric oxide synthase (nNOS)-containing nerves were investigated. Functional in vitro correlates were obtained. An in vivo model was developed in which erectile haemodynamics in response to drugs or nerve-stimulation were studied. 2. Immunoreactivities for vesicular acetylcholine transporter protein (VAChT), nNOS-, and vasoactive intestinal polypeptide (VIP), co-existed in nerve fibres and terminal varicosities. Immunoreactivities for neuropeptide Y (NPY) and tyrosine hydroxylase (TH) were found in the same nerve structures. 3. Chemical sympathectomy abolished TH- and NPY-IR nerve structures in cavernous smooth muscle bundles. The distribution of calcitonin gene-related peptide (CGRP)-, nNOS-, VAChT- and VIP-IR nerve structures was unchanged. 4. In endothelial cells of the central and helicine arteries, veins and venules, intense immunoreactivity for endothelial NOS (eNOS) was observed. No distinct eNOS-IR cells were found lining the cavernous sinusoids. 5. In vitro, nerve-induced relaxations were verified, and endothelial NO/cyclic GMP-mediated relaxant responses were established. VIP and CGRP had small relaxant effects. A functioning adenylate cyclase/cyclic AMP pathway was confirmed. 6. Neuronal excitatory responses were abolished by prazosin, or forskolin. VIP and CGRP counteracted contractions, whereas NPY and scopolamine enhanced excitatory responses. 7. In vivo, erectile responses were significantly attenuated by L-NAME (50 mg kg(-1)) and facilitated by sildenafil (200 microg kg(-1)). 8. It is concluded that the mouse is a suitable model for studies of erectile mechanisms in vitro and in vivo.
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