The influence of the wall tension on the contractile responses of arteries

• Type: Article in International Scientific Journal
• Date: 1999

Authors

José Pedro Nunes (Author) FMUP; Guimaraes, S (Author) Other

Journal

Title: Fundamental and Clinical Pharmacology

Vol. 13

Pages: 193-197

ISSN: 0767-3981

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 4 Citations

Scopus - 4 Citations

Other information

Authenticus ID: P-001-5NQ

Abstract (EN): The present study aimed at determining the influence of tension on the responses of arterial smooth muscle to noradrenaline, phenylephrine and angiotensin II. Concentration-response curves to these agonists were obtained in the rat aorta, at two levels of tension: 3 g (29.4 mN) and 0.5 g (4.9 mN). The results obtained show that the maximal responses to the agonists used tin percent of the maximal response to noradrenaline) were significantly larger (P < 0.05) at 3 g than at 0.5 g: 113% versus 66%, respectively, for noradrenaline; 95% versus 59%, respectively, for phenylephrine; 60% versus 24%, respectively, for angiotensin II. In the presence of gadolinium (100 mu mol/L) - a mechanogated ion channel blocker - the responses to noradrenaline at 3 g were still significantly larger than responses at 0.5 g: 103% versus 67%, respectively. The compound H-7 (20 mu mol/L) - a protein kinase C inhibitor - caused a marked decrease in the maximal responses to noradrenaline at both levels of tension, the responses being reduced to 44% at 3 g and to 20% at 0.5 g. Isradipine (1 mu mol/L)- a calcium channel blocker - caused a slight decrease in the responses to noradrenaline at both levels of tension, the responses being reduced to 86% (3 g) and to 50% (0.5 g). In endothelium-free arterial rings, the responses to noradrenaline at 3 g and 0.5 g were also significantly different: 118% versus 80%, respectively. It is concluded that the tension of the arterial wall is a major factor influencing the effects of vasoconstrictor agents; however the mechanisms underlying this supersensitivity at higher tension remain unknown. (C) Elsevier, Paris.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 5