Protective effects of cyproheptadine on myocardial reperfusion injury in isolated rat hearts

The protective effects of cypro-heptadine (Cyp), an antiserotonin-antihist-aminic agent with calcium channel blocker activity, on myocardial reperfusion injury in isolated Langendorff heart of rats were studied. After a low perfusion [0. 17 ml·min-1, standard Krebs-Henseleit (K-H) buffer without glucose, gassed with 95 % O2+ 5 % CO2] of 60 min followed by a normal K-H buffer perfusion of 20 min, an extensive and severe myocardial injury appeared: a release of lac-tate dehydrogenase (LDH) and creatine kinase (CK), a decrease of superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px) activities, and an increase of malondialdehyde (MDA) content. Serious inhibition of cardiac functions and appearence of arrhythmia, even asystole, were also elicited in the injuried hearts. Cyp (2. 5 and 5 μmol·L-1) effectively antagonized the damage. The results suggested that the protective effects of Cyp on the ischemia-reperfusion injury may be related to its actions of blocking the calcium channel, scavenging the oxygen free radicals , protecting the antioxygen free radical enzymes, and inhibiting the lipid peroxidation in the myocardium.