Irreversible alpha adrenoceptor blocking effects and reversible muscarinic blocking and nicotinic blocking effects of tetramine disulfides on the heart.

Inotropic effects of phenylephrine, carbachol, and butyrylcholine were used in the rabbit left atrium to evaluate respectively alpha adrenoceptor blocking, muscarinic blocking, and nicotinic blocking effects of tetramine disulfides ((RNH(CH2)nNH(CH2)2S-)2 x 4HX). The alpha adrenoceptor blocking potencies of newly synthesized derivatives R = 3',4'-(OH)2-benzyl, n = 5-9, were similar to those of compounds R = 2'-OCH2-benzyl, n = 5-7. Muscarinic blocking and nicotinic blocking potencies of tetramine disulfides were correlated with alpha adrenoceptor blocking potency. Compounds R = 3',4'-(OH)2-benzyl had relatively low muscarinic blocking potencies and compounds R = 2'-OCH3-benzyl had relatively low nicotinic blocking potencies.