BN-50739: a PAF antagonist and limitation of myocardial infarct size.

Anesthetized rats were subjected to coronary artery ligation (CAL) for 72 h and infarct size was measured macroscopically using TTC staining. Systolic blood pressure and ECG were monitored. BN-50739 (5 mg/kg i.p.) decreased the myocardial infarct size in rats. It prevented the loss of R wave, an electrophysiological measure of ischemic injury in this model. In addition, BN-50739 markedly reduced serum malondialdehyde levels elevated as a consequence of CAL. It is speculated that being a PAF antagonist, BN-50739 decreased lipid peroxidation, perhaps by inhibiting migration of PMN cells to the site of ischemic injury through the limited collateral flow available in rat myocardium, and consequently may have reduced the generation of oxygen reactive species. This may be responsible for its beneficial effect in limiting infarct size.