A comparative study with angiotensin II and (des-aspartic acid) -angiotensin II in the anesthetized cats.

The effects of angiotensin II and angiotensin III were studied in chloralose anesthetized and bilaterally adrenalectomized cats. Both peptides caused a dose-dependent increase in blood pressure and reduced the intraluminal pressure of the terminal ileum which was chosen as a parameter for the adrenergic actions of the peptides. Compared to angiotensin II, angiotensin III had 40 times lower agonistic potency in blood pressure but 200 times lower potency in intraluminal pressure. The competitive angiotensin antagonist Sar1-Ile8-angiotensin II, equally inhibited the agonistic effects of both peptides in blood pressure and intestinal motility. From these results it was concluded that specific angiotensin receptors are responsible for pressure as well as adrenergic effects of angiotensin II and angiotensin III.