Endothelium-dependent relaxation to substance P in human umbilical artery is mediated via prostanoid synthesis.
To investigate the relaxatory effect and mode of action of substance P in the human umbilical artery, ring segments of the artery were suspended in organ baths to record the circular motor activity. Substance P induced a significant relaxation in segments with intact endothelium pre-contracted by potassium or 5-hydroxytryptamine. Segments devoid of their endothelium failed to relax when challenged with substance P. The relaxation induced by substance P was inhibited by the cyclo-oxygenase antagonist indomethacin, while the nitric oxide-synthetase inhibitor L-NG-monomethyl-arginine was without effect. These findings suggest that the relaxatory effect of substance P in the human umbilical artery is dependent on an intact endothelium. In contrast to the case in most other vessels, the relaxation is not mediated via the release of endothelium-derived relaxing factor, but seems to be dependent on prostanoid synthesis.
Bodelsson
G
G
Department of Obstetrics and Gynaecology at Malmö, University of Lund, General Hospital, Sweden.
Stjernquist
M
M
D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology; D011453:Prostaglandins / Q000096:biosynthesis*; D013373:Substance P / Q000494:pharmacology*; D014469:Umbilical Arteries / Q000187:drug effects / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects*
D011453:Prostaglandins; D013373:Substance P; D011188:Potassium; D007213:Indomethacin