DOSE‐RESPONSE CURVES FOR ANGIOTENSIN II AND SYNTHETIC ANALOGUES IN THREE TYPES OF SMOOTH MUSCLE: EXISTENCE OF DIFFERENT FORMS OF RECEPTOR SITES FOR ANGIOTENSIN II

Abstract

1 The dose-response curves for angiotensin II and four analogues in rat colon and uterus, and in rabbit aorta, were obtained. 2 The ED₅₀ values of angiotensin II as well as the ED₅₀s and intrinsic activities of angiotensin analogues varied between the three organs. 3 The interaction of two competitive antagonists with angiotensin II receptors was also examined. The K_I values obtained with both antagonists on the uterus differed from the values on the other tissues. 4 It is concluded that angiotensin II receptors may be different in the three organs examined.