CORONARY COLLATERAL VASODILATOR ACTION OF N-ETHOXYCARBONYL-3-MORPHOLINOSYDNONIMINE (SIN-10) IN HEART WITH CHRONIC CORONARY INSUFFICIENCY IN DOGS

Abstract

Effects of the sydnonimine derivatives on cardiovascular system have been studied (1-5), and the results in our laboratory are summarized as follows: 1) the substitution by the group containing nitrogen with —N—N—linkage in the 3-position (SIN-series) showed vasodilator and consequently hypotensive effects resembling to those of nitrites, and 2) N-acylation of imino group of sydnonimine made the compounds stable chemically (6), which probably resulted in gradual development and prolongation of the hypotensive effects as well as in decreased toxicity (4). These findings prompted us to study the effects of the derivatives on coronary collateral circulation, because nitroglycerin, the most important antianginal agent, was reported to dilate the collateral vessels which developed as a result of chronic myocardial ischem:ia (7, 8), and because the effects of agents on the collateral circulation have received considerable attention as one of the approaches to evaluate antianginal activity in laboratory experiment (9).
The present study was carried out to investigate the effects of N-ethoxycarbonyl-3-morpholinosydnonimine (SIN-10) and related compounds on the coronary collateral circulation.