| 1. |
- Poljakovic, Mirjana, et al.
(författare)
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Signalling pathways regulating inducible nitric oxide synthase expression in human kidney epithelial cells
- 2003
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Ingår i: European Journal of Pharmacology. - 0014-2999 .- 1879-0712. ; 469:1-3, s. 21-28
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to elucidate the signalling pathways involved in the cytokine-activated inducible nitric oxide synthase (iNOS) response in a human kidney epithelial cell line, A498. Unstimulated cells did not express iNOS. Exposure of A498 cells to a cytokine mixture consisting of interferon gamma, interleukin-1 beta and tumor necrosis factor-alpha (TNF-alpha) increased nitrite production, iNOS mRNA and protein expression. Pharmacological inhibition of tyrosine kinases, including janus kinase (JAK2), and protein kinase C (PKC) inhibited cytokine-mediated nitrite production and iNOS protein expression. The involvement of mitogen-activated protein kinases (MAPKs) was investigated. Inhibition of p38 MAPK, but not of an upstream activator of extracellular signal-regulated kinase (ERK), caused a decrease in iNOS expression and nitrite production in response to cytokines. Electrophoretic mobility shift assay of nuclear extract from cytokine-stimulated cells demonstrated a pronounced binding to a nuclear factor kappa B (NF-kappa B) sequence present in the human iNOS promoter. Furthermore, the NF-kappa B inhibitor pyrrolidinedithiocarbamate (PDTC) decreased cytokine-activated iNOS protein expression and nitrite production. The present study has demonstrated that cytokine-stimulated iNOS expression in human kidney epithelial cells involves activation of tyrosine kinases, including JAK2, PKC, p38 MAPK and NF-kappa B.
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| 2. |
- Elmi, Adrian, et al.
(författare)
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Modulation of islet ATP content by inhibition or stimulation of the Na(+)/K(+) pump
- 2001
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Ingår i: European Journal of Pharmacology. - : Elsevier. - 0014-2999 .- 1879-0712. ; 426:1-2, s. 139-143
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Tidskriftsartikel (refereegranskat)abstract
- High (30 mM) K(+), known to cause beta-cell membrane depolarisation, significantly decreased the islet total ATP content, supporting the view that beta-cell membrane depolarisation can activate the ATP-consuming Na(+)/K(+) pump. Ouabain (1 mM) did not change the islet ATP content after 5-15 min of incubation in the absence or presence of 3 mM glucose but reduced it after 30 min, and in the presence of 20 mM glucose, the reduction by ouabain occurred already after 15 min. Incubation of islets with ouabain for 60 min decreased the islet ATP content in the presence of 3, 10 or 20 mM glucose or 30 mM K(+). Also, the islet glucose oxidation rate was decreased by ouabain. When K(+) deficiency was used to inhibit the Na(+)/K(+) pump, no change in ATP content was observed irrespective of glucose concentration, although K(+) deficiency caused a slight inhibition of the glucose oxidation rate. Diazoxide reduced the islet glucose oxidation rate and increased the islet ATP content in the presence of 20 mM glucose. There may exist a feedback mechanism decreasing the flow of glucose metabolism in response to reduced ATP consumption by the Na(+)/K(+) pump.
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| 3. |
- Persson, Karin, et al.
(författare)
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Nitric oxide donors and angiotensin-converting enzyme inhibitors act in concert to inhibit human angiotensin-converting enzyme activity and platelet aggregation in vitro
- 2000
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Ingår i: European Journal of Pharmacology. - 0014-2999 .- 1879-0712. ; 406:1, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the effects of exogenous and endogenous nitric oxide (NO) on human circulating and endothelial angiotensin-converting enzyme activity and platelet aggregation. The NO donor S-nitroso-N-acetylpenicillamine (10-8-10-6 M) significantly and dose-dependently inhibited serum angiotensin-converting enzyme activity. The concomitant addition of S-nitroso-N-acetylpenicillamine to angiotensin-converting enzyme inhibitor-treated (captopril or enalaprilat) serum, further reduced angiotensin-converting enzyme activity. In cultured endothelial cells from human umbilical veins (HUVECs), both S-nitroso-N-acetylpenicillamine and 3-morpholinosydnonimine (SIN-1) significantly reduced angiotensin-converting enzyme activity. An additative effect was seen with a combined treatment of captopril and S-nitroso-N-acetylpenicillamine. Treatment with the NO synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA) did not affect angiotensin-converting enzyme activity. Thrombin inhibited endothelial angiotensin-converting enzyme activity, an effect that was abolished when cells were pretreated with L-NMMA. Adenosine 5'-diphosphate (ADP)-induced platelet aggregation was inhibited with S-nitroso-N-acetylpenicillamine, SIN-1 and nitroglycerine. Captopril did not affect aggregation, while a high concentration of enalaprilat (10-4 M) reduced it. The concomitant addition of 10-5 M angiotensin-converting enzyme inhibitor to NO donor-treated platelets resulted in a further reduction of platelet aggregation. This effect was most evident with SIN-1 and enalaprilat. In conclusion, both exogenous and endogenous NO inhibit human angiotensin-converting enzyme activity. NO donors and angiotensin-converting enzyme inhibitors act in concert to inhibit angiotensin-converting enzyme and platelet aggregation. Copyright (C) 2000 Elsevier Science B.V.
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| 4. |
- Spetea, M, et al.
(författare)
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Alteration in endogenous systems during chronic inflammatory pain conditions
- 2002
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Ingår i: European Journal of Pharmacology. - 0014-2999 .- 1879-0712. ; 435:2-3, s. 245-252
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Tidskriftsartikel (refereegranskat)abstract
- The influence of chronic arthritic pain on two endogenous opioid peptides, dynorphin B and [Met5]enkephalin-Arg6-Phe7, and multiple opioid receptors in discrete brain, lumbar spinal cord and pituitary pools was investigated. Using radioimmunoassay and receptor binding assay, we examined the changes in regional opioid peptide levels and opioid receptor activity due to chronic inflammation in adjuvant arthritic rats. At 4 weeks post-inoculation, increased levels of immunoreactive dynorphin B and [Met5]enkephalin-Arg6-Phe7 were measured in tissues of arthritic rats compared with controls. No significant changes in mu-, delta- or kappa-opioid receptors were seen after chronic inflammation. Taken together, these results indicate that in chronic arthritis, opioid receptor changes do not follow the peptide alterations of pro-dynorphin and pro-enkephalin systems. Thus, dynamic modification and modulation of nociceptive information takes place during chronic inflammation. This supports the key role of the central nervous system in chronic inflammatory pain conditions.
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| 5. |
- Zemgulis, Vitas, et al.
(författare)
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Nucleoside transport inhibition in ischemic myocardium results in enhanced taurine efflux
- 2001
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Ingår i: European Journal of Pharmacology. - 0014-2999 .- 1879-0712. ; 411:1-2, s. 143-154
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We measured with the microdialysis technique energy-related metabolites in ischemic myocardium over time in an experimental pig model. Emphasis was put on the dipyridamole effect when administered in the microdialysis probe inserted in ischemic myocardium. Not only adenosine but also taurine and pyruvate concentrations were significantly higher in the microdialysate during the periods of ischemia and extracorporeal circulation with cardioplegia. The enhanced efflux of taurine in ischemic myocardium induced by dipyridamole is a new finding. A mechanistic role of taurine in the prevention of Ca(2+) overload in ischemic myocytes is discussed. Also, taurine may have stimulatory effects on glycolysis in ischemic heart.
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| 6. |
- Asplund Persson, Anna K, et al.
(författare)
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Characterisation of GEA 3175 on human platelets : comparison with S-nitroso-N-acetyl-D,L-penicillamine
- 2004
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 496:1-3, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- By comparing the effect of two nitric oxide (NO)-containing compounds, we found that S-nitroso-N-acetyl-d,l-penicillamine (SNAP), but not GEA 3175 (1,2,3,4-Oxatriazolium,3-(3-chloro-2-metylphenyl)-5-[[(4-methylphenyl)sulfonyl]amino]-, hydroxide inner salt), released NO. Despite this, both drugs elevated cyclic guanosine 3′,5′-monophosphate (cGMP) levels in human platelets. However, SNAP was more effective after short exposure times (5 and 20 s). The compounds also inhibited thrombin-induced rises in cytosolic Ca2+. Time studies revealed that the action of SNAP rapidly declined by increasing the length of incubation (from 5 s to 30 min). This desensibilisation phenomenon mainly involved the release of Ca2+ from intracellular stores. In comparison, GEA 3175-induced inhibition of cytosolic Ca2+ signalling was much more long-lasting. The soluble guanylyl cyclase (sGC) inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) reversed the effect of GEA 3175 on cytosolic Ca2+. Consequently, this inhibition depends solely on the increase in cGMP. In summary, differences between GEA 3175 and SNAP were observed in NO releasing, cGMP elevating and Ca2+ suppressive properties.
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| 7. |
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| 8. |
- Eghbali, Mansoureh, et al.
(författare)
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Effects of propofol on GABAA channel conductance in rat-cultured hippocampal neurons.
- 2003
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Ingår i: European Journal of Pharmacology. - 0014-2999 .- 1879-0712. ; 468:2, s. 75-82
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Tidskriftsartikel (refereegranskat)abstract
- Channels were activated, in ripped-off patches from rat-cultured hippocampal neurons, by propofol alone, propofol plus 0.5 microM GABA (gamma-aminobutyric acid) or GABA alone. The propofol-activated currents were chloride-selective, showed outward-rectification and were enhanced by 1 microM diazepam. The maximum propofol-activated channel conductance increased with propofol concentration from less than 15 pS (10 microM) to about 60 pS (500 microM) but decreased to 40 pS in 1 mM propofol. Fitting the data from 10 to 500 microM propofol with a Hill-type equation gave a maximum conductance of 64 pS, an EC50 value of 32 microM and a Hill coefficient of 1.1. Addition of 0.5 microM GABA shifted the propofol EC50 value to 10 microM and increased the maximum channel conductance to about 100 pS. The Hill coefficient was 0.8. The maximum channel conductance did not increase further when 1 microM diazepam was added together with a saturating propofol concentration and GABA. The results are compared to effects other drugs have on GABAA channels conductance.
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| 9. |
- Jansen-Olesen, I, et al.
(författare)
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In-depth characterization of CGRP receptors in human intracranial arteries
- 2003
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 481:2-3, s. 207-216
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present study was to characterize the effects of human (h) alpha- and beta-calcitonin gene-related peptide (CGRP) on intracranial arteries from man and to investigate the presence of mRNA for the calcitonin receptor like receptor (CRLR) and the receptor activity modifying proteins (RAMPs) 1, 2 and 3, in cerebral and middle meningeal arteries with and without endothelium, in microvessels and in the endothelial cells isolated from the human basilar artery. Reverse transcriptase-polymerase chain reaction (RT-PCR) revealed the presence of CRLR, RAMP 1, RAMP 2 and RAMP 3 in cerebral and middle meningeal arteries with and without endothelium as well as in microvessels and in the endothelial cells. Human and rat a- and p-CGRP, amylin, adrenomedullin and [acetamidomethyl-Cys(2,7)]human CGRP induced strong concentration-dependent relaxation of human cerebral and middle meningeal arteries. Removal of the endothelium neither changed the maximum relaxant response nor the pIC(50) values for alpha- and beta-CGRP as compared to the responses in arteries with an intact endothelium. Human alpha-CGRP-(8-37) caused a shift of halpha- and hbeta-CGRP-induced relaxations in cerebral and middle meningeal arteries. Calculation of pK(B) values revealed that halpha-CGRP-(8-37) could not significantly discriminate between relaxations induced by halpha-CGRP (pK(B) around 6.8) and hbeta-CGRP (pK(B) around 5.4). There was no significant difference in pK(B) value of halpha-CGRP-(8-37) on hbeta-CGRP-induced relaxation of human cerebral and middle meningeal arteries with and without endothelium. In conclusion, our molecular and pharmacological data support the existence of a single type of CGRP(1) receptors in the human intracranial circulation. (C) 2003 Elsevier B.V. All rights reserved.
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| 10. |
- Jonsson, M., et al.
(författare)
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Neuromuscular blocking agents block carotid body neuronal nicotinic acetylcholine receptors
- 2004
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 497:2, s. 173-180
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Tidskriftsartikel (refereegranskat)abstract
- Neuromuscular blocking agents predominantly block muscle type nicotinic acetylcholine receptors as opposed to the neuronal type. However, there is growing evidence that neuromuscular blocking agents have affinity to some neuronal nicotinic acetylcholine receptors. The carotid body chemoreceptor as the essential oxygen-sensing cell, relies on cholinergic signalling. Atracurium and vecuronium impair carotid body chemoreceptor activity during hypoxia. Here, we characterize atracurium and vecuronium as antagonists at nicotinic receptors of the carotid body chemoreceptor. Isolated rabbit carotid body preparations with carotid sinus nerve were used, and chemoreceptor activities were recorded. There was a concentration-dependent reduction in the chemoreceptor responses to nicotine, with an IC50 to 50 µg nicotine of 3.64 and 1.64 µM and to 500 µg nicotine of 27.00 µM and 7.29 µM for atracurium and vecuronium, respectively. It is concluded that atracurium and vecuronium depress nicotine-induced chemoreceptor responses of the carotid body in a dose-dependent fashion. © 2004 Elsevier B.V. All rights reserved.
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