SOME FUNCTIONAL-ASPECTS OF THE RENIN-ANGIOTENSIN SYSTEM IN THE SNAKE BOTHROPS-JARARACA

Vasopressor and steroidogenic effects of synthetic angiotensin [Asn(1), Val(5)] AII and Bothrops jararaca crude renin were compared in anesthetized Bothrops jararaca snakes. While the intravenous infusion of [Asn(1), Val(5)] AII (2.0 mu g/kg/min) promoted an arterial blood pressure elevation of 18.2 +/- 2.7 mmHg but had no detectable steroidogenic effect, Bothrops jararaca crude renin (0.4 ml/kg/min) induced an increase of both, mean arterial blood pressure (12.8 +/- 2.0 mmHg) and plasma corticosterone concentration (85.8 +/- 20.1 ng/ml). In vitro experiments indicated that the relative potencies of synthetic angiotensins were [Asn(1), Val(5)] AII < [Asp(1), Ile(5)] AII = [Asp(1), Val(5)] AII in B. jararaca uterus, but [Asn(1), Val(5)] AII > [Asp(1), Ile(5)] AII in the guinea-pig ileum. The results indicate that the renin-angiotensin system may be important for the control of blood pressure and steroidogenesis in the snake, although some differences in the structural requirements for angiotensin action occur in this animal when compared to mammals.