Free radical scavenger mechanisms in experimentally induced ischemia in the rabbit heart and protective effect of verapamil.

The protective effect of verapamil on the free radical generation in the ischemic myocardium of rabbit has been studied. A significant decrease of the lactate dehydrogenase activity in the ischemic zone was observed compared to the nonischemic control myocardial tissue. The level of malondialdehyde was found to be elevated in the ischemic zone and in other parts of the myocardium. However, there was no alteration in glutathione content in both zones. In addition, an increase in the activity of myeloperoxidase was observed in the ischemic part of the myocardium. At lower doses (30 micrograms/kg), verapamil protected the animals from ischemic changes but did not do so at higher doses (100 micrograms/kg). These results suggest that, in the rabbit, the free radical scavenging mechanism of the heart is not adversely affected during ischemia.