Calcium dependency of the angiotensin II-induced vasoconstriction in the rat.
In the present study we investigated the effect of different calcium antagonists on the constrictor effect of angiotensin II (Ang II) in two vascular preparations of the rat, the coronary and the mesenteric arterial beds. In contrast to the coronary bed, vasoconstriction elicited by Ang II in the rat mesentery could in part (1/3) be explained by a release of noradrenaline from the sympathetic nerve endings. In both preparations the calcium antagonists inhibited the vasoconstrictor effect of Ang II to the same extent (about 65%). In the pithed rat, the increase in diastolic blood pressure induced by Ang II could only be inhibited by the calcium antagonists by approximately 40%. Since this model only reflects overall changes in peripheral resistance, regional differences may lead to greater beneficial effects from the calcium antagonists in certain vascular beds.
van Heiningen
P N
PN
Department of Pharmacotherapy/Pharmacology, University of Amsterdam, The Netherlands.
Bohnenn
V A
VA
van Zwieten
P A
PA
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology
D002121:Calcium Channel Blockers; D000804:Angiotensin II; D002118:Calcium