Is the cardiovascular effect of nitroglycerin related to the prostaglandin system in the dog?

Open-chest dogs were used for studies of the effects of intra-coronary (0.3-10 micrograms) or i.v. nitroglycerin (0.3-100 micrograms/kg) on systemic blood pressure (SBP), heart rate, left ventricular (LV) pressure, coronary blood flow and vascular resistance in the absence of presence of indomethacin (3 mg/kg i.v.). The nitroglycerin-induced changes in the cardiovascular parameters were not significantly modified by indomethacin (3 mg/kg i.v.). The dose of indomethacin used was large enough to inhibit significantly, for more than 2 h, the coronary vasodilation induced by arachidonic acid (100 micrograms) administered intra-arterially. The present study suggests that the cardiovascular action of nitroglycerin may not be mediated through the prostaglandin system.