EFFECT OF CAPTOPRIL CARDIOPLEGIA ON RENIN-ANGIOTENSIN SYSTEM, PROSTAGLANDINS, FREE-RADICALS AND ELECTROLYTES IN THE ISOLATED HYPOTHERMIC ISCHEMIC AND REPERFUSION RABBIT HEARTS

The effect of captopril cardioplegia on ischemic and reperfusion myoca rdium after 3 hours of hypothermic (13 +/- 1-degrees-C ) arrest and 35 minutes of reperfusion was studied in the isolated working rabbit hea rt. In comparision with the control group, captopril cardioplegia redu ced the content of angiotensin II (381 +/- 56 vs 507 +/- 84 pg / g wt of the control group, P < 0.01) and MDA (50.0 +/- 9.2 vs 85.1 +/- 16.1 pmol / mg pr, P < 0.01) in the reperfusion myocardium; augmented the renin activity of ischemic (1050 +/- 353 vs 669 +/- 301 pg / g wt / h, P < 0.05) and reperfusion myocardium (1261 +/- 421 vs 498+/- 353 pg/g wt/h, P < 0.01) increased the 6-K-PGF1alpha / TXB2 ratio in the reper fusion myocardium (by 48.1% of the control group). Meanwhile, captopri l cardioplegia could also decrease the content of calcium (0.027 +/- 0 .015 vs 0.045 +/- 0.014 muM / mg pr, P < 0.05) and sodium (0.54 +/- 0. 26 vs 0.82 +/- 0.15 muM/mg pr, P < 0.05) in the reperfusion myocardium , but had no effect on the potassium content. The results show that th e protective effect of captopril on hypothermic myocardium may be rela ted to the free radical scavenging action, inhibition of angiotensin I I production, improvement of PGI2 / TXA2 ratio and decrease of calcium and sodium overload in the myocardium.