The protective effects of verapamil on the ischemic rat liver perfused with Ca²⁺-free medium

A study to investigate the effectiveness of verapamil in reducing ischemic damage was performed using the isolated rat liver preparation perfused with the Ca²⁺-free solution and subjected to zero-flow ischemia of 60 min duration. Verapamil as high as 0.2 mg kg^-1 b.w., given in the perfusion medium prior to ischemia was protective as revealed by a lower transaminase (GPT) release, 500 U L^-1, compared with the ischemic group without verapamil, 1121 U L^-1 (p < 0.05), but not significantly different from control, 424 U L^-1. After 30 min reperfusion the transaminase activities were found to be 1087 U L^-1 in the verapamil-pretreated group, 1296 U L^-1 in the ischemic group without verapamil and 418 U L^-1 in the control group, suggesting the occurrence of oxygen paradox and that verapamil could not alter the event. Nevertheless, the trypan blue uptake of the verapamil group was similiar to control and significantly lower than that in the ischemic group without verapamil. The mechanism by which verapamil may ameliorate the ischemic liver damage is unknown and needs further investigation.