Effects and interaction of nicardipine and volatile anesthetics in the rat heart-lung preparation.

The effects of the calcium channel blocker nicardipine (N) and the volatile anesthetics halothane (H), enflurane (E), isoflurane (I), and sevoflurane (S) on myocardial metabolism after postischemic reperfusion were assessed in the isolated rat heart-lung preparation. Wistar-ST rats were randomly divided into six groups (each groupn=9) as follows: control (C) group, no drugs; N group, N (100 ng·ml-1); H group, 1% H and N; E group, 2.2% E and N; I group, 1.5% I and N; and the S group, 3.3% S and N. In the presence of the volatile anesthetics, the preparations were perfused for 10 min, made globally ischemic for 8 min, and then reperfused for 10 min. N 100 ng·ml-1 was administered 5 min before ischemia except in the C group. Three hearts in the C and H groups (eachn=9) and one heart in the E group (n=9) failed to recover from ischemia. The recovery times in the N, I and S groups were significantly shorter than controls. Although there was no significant difference in myocardial lactate concentrations among the groups, ATP content in the N, H, E, I and S groups was significantly higher than in controls. Glycogen content in the N, E, I and S groups was also significantly higher than in controls. These results suggest that N improves myocardial recovery from ischemia; however, in the presence of H or E it may cause significant myocardial depression.