[Effects of prostacyclin on the cardiac functions and energy metabolism in the perfused rat heart].
Recently, prostacyclin (PGI2) has been reported to have a role of potential importance in myocardial ischemia. The direct effects of PGI2 on ischemic myocardial injury (60 minutes ischemia at 30 degrees C) were examined, using a hemoglobin free isolated rat heart perfused by the Langendorff's technique. Dual-wavelength reflectance spectrophotometry was used to measure myoglobin oxygenation in cardiac tissue, from which the intracellular oxygen concentration was calculated. The effect of PGI2 on cardial function under normoxic perfusion condition was studied. PGI2 was infused for 10 minutes with the doses of 5ng/g X body weight per minute. PGI2 infusion increased heart rate, LV dp/dt and myocardial oxygen consumption. The average 9.7% increase in myoglobin oxygenation was noted during PGI2 infusion which indicated the improvement in tissue oxygen metabolism. The global ischemia was produced for 60 minutes at 30 degrees C, following to the pretreatment of 10 minutes infusion of PGI2, by the discontinuation of Langendorff's perfusion. Recovery of cardiac function such as double product and LV dp/dt at 15 minutes after reperfusion was significantly higher in the PGI2 treated group than in hearts receiving only the vehicle. Infusion of PGI2 inhibited the decrease in ATP level of the ischemic myocardium at 15 minutes after reperfusion (P less than 0.025, P less than 0.05). PGI2 prevented the increase in lactate release from the ischemic myocardium, observed in vehicle group at 1 minutes after reperfusion. In summary, prostacyclin seems to have a direct cytoprotective effect on ischemic myocardium.
D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000503:physiopathology; D004734:Energy Metabolism / Q000187:drug effects*; D011464:Epoprostenol / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
D011464:Epoprostenol