Cardiac and vascular actions of decapeptide angiotensin analogs.

摘要: We have reported previously the characterization of angiotensin (A) II myocardial receptor and provided biological evidence that inotropic activities octapeptide AII are mediated. In addition to this compound demonstrates, it also has potent vascular contractile activities. The decapeptide AI exhibits both cardiac (+)-inotropic responses in large part secondary conversion smaller peptides, principally AII. To attempt separate response these several A analogs with amino acid substitutions either 1, 5 or 7 positions were studied. compounds as follows: [Sar1Ile5Ala7]AI; [Sar1Ile5 alpha-MeAla7]AI; [Sar1Val5N-MeAla7]AI [Sar1Val5Sar7]AI. These studied rabbit point-stimulated left atria, isometrically contracting aortic rings competition for [125I]AII binding ventricular membranes. All peptides exhibited partial agonist tissues potencies equivalent less than AI. decapeptides was decreased presence converting enzyme inhibitor enalaprilat. suggest may be responsible peptides. Biologically active obtained no. positions. Sarcosine substitution position 1 did not enhance potency observed analogs.