Abstract
Effects of various coronary vasodilators on the coronary, the femoral and the renal circulations were compared with those of nitroglycerin, and classified on the basis of differences in the mode of action. Coronary vasodilators used in this study, caused a significant increase in the rate of both the coronary and the femoral blood flows while a slight increase or even a decrease in the rate of the renal blood flow was observed. The coronary vasodilating activity was in the following order; nifedipine>nitroglycerin>iproveratril>dipyridamole, prenylamine, lidoflazine, papaverine>carbochromene, trapymin>khellin, which was approx. equivalent to 1: 1/3: 1/10: 1/100: 1/300: 1/3000. The order of effectiveness of vasodilation in the coronary circulation produced by these compounds was similar to that observed in femoral circulation. Lidoflazine, dipyridamole, prenylamine, carbochromene and khellin, however, caused a dose-dependent vasoconstriction in renal circulation. A large dose of papaverine caused a diphasic response in the renal circulation. From these experimental results, lidoflazine, dipyridamole, carbochromene and khelline can be classified as “specific coronary vasodilators”, while nifedipine, nitroglycerin, iproveratril and trapymin are “non-specific coronary vasodilators”. Papaverine and prenylamine do not appear to belong to these two categories.
