Enhancement of Coronary Vasodilating Action of ATP and Adenosine by Lidoflazine

Lidoflazine, a newly developed coronary vasodilator, greatly enhances the coronary vasodilating action of adenosine and ATP. Experiments were designed to study the combined coronary vasodilating effects of adenosine and lidoflazine and to quantify the enhancement of coronary vasodilation of adenosine and ATP by prior administration of lidoflazine. Results of the experiments showed that the combined coronary vasodilating effects of adenosine and lidoflazine can be classified as supra-additive. For 3 hours after the administration of lidoflazine there was a great intensification (20 to 150 times) of the vasodilating action of adenosine or ATP. An adenosine-sparing effect of lidoflazine in whole blood was also demonstrated, and the enhancement of adenosine action is in part related to this effect. It is suggested that lidoflazine may also produce a change in the sensitivity of the smooth muscle of the coronary vessels to the direct or indirect action of adenosine.