کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2537258 | 1559184 | 2006 | 5 صفحه PDF | دانلود رایگان |
In human resistance arteries the role of intracellular calcium during receptor agonist and nitric oxide (NO)-mediated vasorelaxation is almost unknown. We examined changes in smooth muscle calcium concentration ([Ca2+]i) caused by acetylcholine and the NO donor S-nitroso-N-acetylpenicillamine (SNAP) in isolated human subcutaneous small arteries. In arteries constricted with 50 mM KCl, acetylcholine and SNAP induced relaxation without any change in [Ca2+]i, whereas in noradrenaline constricted vessels, both acetylcholine and to a lesser degree also SNAP-mediated relaxation were associated with a decrease in [Ca2+]i. Furthermore incubation with SNAP (1 μM) induced a rightward shift in the [Ca2+]i–force relationship. These results suggest that relaxation mediated by endothelium derived hyperpolarizing factors (EDHF) is associated with reduction in [Ca2+]i, whereas NO-mediated relaxation can take place without changes in [Ca2+]i. This finding seems to be, at least partly, due to NO-mediated desensitization of the contractile apparatus to calcium.
Journal: European Journal of Pharmacology - Volume 535, Issues 1–3, 27 March 2006, Pages 243–247