Effect of ischaemia and pharmacological treatment on enzyme activities of cortical mitochondria and synaptosomes

Changes in the maximal rate of some enzymatic activities related to energy transduction (lactate dehydrogenase; citrate synthetase and malate dehydrogenase; total NADH-cytochrome c reductase and cytochrome oxidase) and others such as glutamate dehydrogenase and acetylcholine esterase were assayed both in the purified mitochondrial fraction and in the crude synaptosomal fraction from the cerebral cortex of rats. The evaluations were performed before and after a postdecapitative normothermic ischaemia of 5, 10, 20 and 40 min duration. The ischaemic damage resulted in a decrease in the activity of mitochondrial malate dehydrogenase and total NADH-cytochrome c reductase, and of synaptosomal acetylcholine esterase. The biochemical evaluations were performed also after an intraperitoneal pretreatment with vincamine TPS, trimetazidine DC and suloctidil (50 mg/kg). These drugs induced different changes in enzyme activities as a function of the duration of ischaemia. These various interferences are discussed with regard to the possible mode of action of the drugs