Characterization of angiotensin pressor responses in the turtle Pseudemys scripta.
Studies were conducted in turtles (Pseudemys scripta) to characterize vascular responses to administration of exogenous angiotensin [Asp1-Ile5]angiotensin II (AII). Marked pressor responses were present following AII administration (2 microgram/kg iv). The pressor response was completely blocked by concomitant administration of an analogue of AII, [Sar1-Ile8]AII. Both alpha-receptor blockade with phenoxybenzamine or catecholamine depletion by reserpine administration reduced the pressor response approximately 50%. Further treatment with [Sar1-Ile8]AII completely blocked the AII pressor response. We conclude that the pressor response to AII in this species that represents an ancient group of reptiles includes a catecholamine-dependent component and direct vascular receptors, both of which are sensitive to AII.
D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001808:Blood Vessels / Q000294:innervation; D010643:Phenoxybenzamine / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000502:physiology; D012110:Reserpine / Q000494:pharmacology; D014426:Turtles / Q000502:physiology*
D011941:Receptors, Adrenergic; D010643:Phenoxybenzamine; D000804:Angiotensin II; D012110:Reserpine; D015059:1-Sarcosine-8-Isoleucine Angiotensin II