title: Increase in the coronary vascular resistance by indomethacin in the isolated guinea pig heart preparation in the absence of changes in mechanical performance and oxygen consumption.
abstract: Experiments were performed in isolated guinea pig hearts, perfused at constant volume. Left ventricular pressure, left ventricular dp/dtmax, coronary vascular pressure and coronary venous pO2 were measured continuously. Indomethacin (1.4 X 10(-6) M) increased coronary vascular resistance by 15% over control (p less than 0.01) without altering the myocardial contractile force. When PGE2 (1.4 X10(-8) M) was subsequently added, it abolished the indomethacin action and lowered the coronary vascular resistance below the pre-indomethacin control value. This increase in coronary vascular resistance caused by indomethacin was also seen when the animals were pretreated with reserpine and/or the adrenoceptor blocking agents phenoxybenzamine and propranolol, but was prevented completely by previous addition of PGE2 (1.4 X 10(-7) M). The results provide evidence for possible involvement of endogenous prostaglandin-like substances in the maintenance of coronary vascular resistance in the isolated guinea pig heart.
mesh_terms: D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects*; D005260:Female; D006168:Guinea Pigs; D006439:Hemodynamics / Q000187:drug effects*; D066298:In Vitro Techniques; D007213:Indomethacin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects*; D010643:Phenoxybenzamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology; D012110:Reserpine / Q000494:pharmacology; D013268:Stimulation, Chemical; D014439:Tyramine / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects*
chemical_list: D011458:Prostaglandins E; D010643:Phenoxybenzamine; D012110:Reserpine; D011433:Propranolol; D014439:Tyramine; D007213:Indomethacin