Protective effects of nitrendipine against myocardial infarction in rabbits

In rabbits the left circumflex coronary artery was ligated for 24 h. Nitrendipine (Nit) 10 mg.kg-1 ig were given 1 h before ligation and 1, 4, and 7 h after ligation. Nit decreased myocardial infarctive size (MIS) from 25.2 +/- 1.7% to 15.5 +/- 1.6% (P < 0.01), lowered serum creatine kinase (CK) and lactate dehydrogenase isoenzyme 1 (LDH1) from 381 +/- 69 IU.L-1 and 42 +/- 6% to 281 +/- 49 IU.L-1 (P < 0.01) and 31 +/- 8% (P < 0.05), diminished injury of myocyte ultrastructure, especially mitochondria and myofibrillae, in ischemic and infarctive zone. Nit exerted no significant effect on plasma level of norepinephrine (NE). The results indicate that Nit has protective effects against the acute myocardial infarction.