Effects of lisinopril and captopril on calcium in rat heart.

We studied the effects of lisinopril (Lis) and captopril (Cap), two angiotensin-converting enzyme inhibitors, on calcium in ischemia/reperfusion and normal rat hearts. Ischemia/reperfusion hearts were subjected to 15 min ischemia followed by 1 or 30 min reperfusion. Lis 0.1 mumol.L-1 and Cap 200 mumol.L-1 decreased the concentration of calcium in ischemia/reperfusion hearts (the content of calcium in reperfusion 1 min heart were reduced from 4.0 +/- 0.6 to 2.7 +/- 0.5 and 3.0 +/- 0.9 mumol/g dry wt respectively). In cultured cell of neonatal rat heart, both drugs inhibited the uptake of 45Ca2+. The activity of Na+,K(+)-ATPase prepared from rat heart was increased (activity increased from 15.7 +/- 2.3 in control group to 21.2 +/- 2.0 and 22.0 +/- 3.1 mumol/h mg protein in Lis and Cap groups, respectively). This calcium lowering effects of Lis and Cap may be important in protecting the ischemia/reperfusion damage of myocardium.