Contractile responses of isolated dog mesenteric arteries to angiotensin I, II and III.
The addition of angiotensin (Ang-) I, II and III caused a dose-dependent contraction of helically cut strips of dog mesenteric arteries. Tachyphylaxis developed following repeated additions of angiotensins. Average median effective concentrations of Ang-I, II and III were 3.7, 0.8 and 2.5 X 10(-8) M, respectively. Contractile responses to the angiotensins were attenuated to a similar extent by Ang-II antagonists, Sar1 Ileu8 Ang-II and Sar1 Ala8 Ang-II, but were unaffected by phentolamine, methysergide and diphenhydramine. The response to Ang-I was significantly reduced by treatment with bradykinin-potentiator B, while the response to Ang-II was not influenced. It may be concluded that Ang-I, II and III produce contractions possibly by activation of same Ang-II receptors and that contractions induced by Ang-I are associated, to some extent, with a conversion to Ang-II in the arterial wall.
D000803:Angiotensin I / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000805:Angiotensin III / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000809:Angiotensins / Q000494:pharmacology*; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D012504:Saralasin / Q000494:pharmacology; D014662:Vasoconstrictor Agents
D000809:Angiotensins; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D000805:Angiotensin III; D000803:Angiotensin I; D012504:Saralasin; D001920:Bradykinin