The Effect of Verapamil Administred before the Reperfusion Insult in Isolated Preconditioned Rat Heart on the Microsomal ATPase and Mitochondrial Enzyme Activities

Background: calcium overload and free radical mediateddamage in the mitochondria is the most important pathologicalchanges associated with myocardial ischemicreperfusioninjury. the verapamil post-treatment has beenpreviously reported to prevent reperfusion-induced myocardialinjury but functional recovery may be delayed dueto the drug's inherent direct myocardial depression effect.in the present study the effect of verapamil on mitochondrialenzymes and sarcoplasmic atpase system was examinedduring the myocardial preconditioning and ischemicreperfusion in rat heart.methods: four groups of isolated rat hearts were perfusedwith kh buffer in a retrograde manner by lagendroff apparatus. a time controlled ischemia, ischemic reperfusion andclassical precondition was produced by restoring the flow ofkh buffer in ischemic rat heart. the hearts were then processedto isolate the mito chondria and sarcoplasmic reticulumfor the biochemical est imation.results: mitochondrial enzyme and sarcoplasmic atpaseactivities were diminished in the ischemic period and furtherdecreased during reperfusion . however, preconditioning therat heart before the insult of ischemia and reperfusion improvedthe enzyme activities. the preconditioning procedureconsisted of 4 cycles of 4 min. short ischemic periods followedby 4 min. kh buffer perfusion applied before 30 min.global ischemia and reperfusion caused an improvement in themitochondrial enzyme activities. on the other hand, sarcoplasmicatpase enzymes required a precondition procedureof 7 cycles of 2 min. short ischemic periods followed by 2min. reperfusion. the activities of the above enzymes wereimproved further when verapamil was administered before theinsult of ischemic reperfusion.conclusion: this study shows the beneficial effect of classicalpreconditioning with verapamil.