Effects of Verapamil on the Mitochondrial Respiration of Ischemic Kidney in Rabbits

Chang, Sae Yong; Chai, Soo Eung

Abstract

Calcium has been implicated as primary pathogenetic mediator of cellular injury under conditions or oxygen and substrate deprivation in the kidney as well as other tissues. According to various studies, calcium channel blockers may prevent metabolic disturbances and promote functional and structural recovery after ischemia. Verapamil is known to have many actions which may account for its beneficial effect in renal ischemia. The purpose of the present study was to determine the effects of verapamil on mitochondrial respiration of ischemic kidney in rabbits. 1. In normal kidneys, cortical mitochondria showed higher S3 respiration and ACR than medulla But S4 respiration was similar between cortex and medulla. 2. After renal artery clamping in normothermia, there was a marked decrease in S3 respiration, no significant changes in S4 respiration, and a decrease in the ACR in cortex. But in medulla, there were significant decrease in both S3 and S4 respiration with slight decrease in the ACR. 3. In regional hypothermic group, there were a decrease in S3 respiration and a decrease in the ACR on cortex. But S3 respiration and the ACR were significantly higher than those of normothermic group. 4. In verapamil treated group, there was a decrease in S3 respiration and a decrease in the ACR on cortex. But reduction rate of S3 respiration and the ACR was significantly lower than those of normothermic group. 5. In medulla, reduction rate of the ACR was not significantly different between three experimental groups. Above results suggested that verapamil has partial but significant protective effect in renal ischemia and achieve its effect by preserving mitochondrial functions. And also it was suggested that regional hypothermia had a superior protective effect compared with verapamil.