Enhancement of metabolic coronary vasodilatation by nicotinic acid or amide

Cardiostimulation produced by noradrenaline, glucagon, or tachycardia on the isolated perfused rat heart produced a metabolic coronary dilatation that was potentiated by nicotinic acid or its amide [NIC; 0.05-1.0 mM] without affecting the cardiostimulation. Reactive hyperaemia to brief coronary occlusion was unaffected by NIC, thus confirming that its vasodilator mechanism is of a different nature than that leading to metabolic coronary dilatation. It is suggested that NIC may be of significance as an adjuvant in the treatment of certain types of coronary insufficiencies.