The effect of calcium channel blockers on experimental hypercholesteremia in rabbits. Biochemical and histochemical study

Calcium ions act as intracellular messengers in numerous cellular functions and participate also in the development of the atherosclerotic process. Calcium homeostasis could be an important factor in the development of atherosclerosis. One of the drugs which interferes with calcium homeostasis are calcium channel blockers. A number of studies have investigated the possibility whether these drugs may be also useful for prevention of atherosclerosis. However, other investigators have reported that calcium channel blockers did not suppress the atherosclerotic process. In our work we assumed the direct influence of calcium channel blockers on transendothelial transport mechanisms. Therefore we decided to investigate the influence of verapamil, diltiazem and isradipine on the development of experimental atherosclerosis in rabbits. Verapamil administered twice daily, 0.125 mg per kg s. c., reduced the size of atheromatous plaques in the thoracic aorta and the level of total cholesterol and triglycerides in serum. This above effect was not present after administration of diltiazem in doses of 1.0 mg per kg and isradipine 1.25 mg per kg twice daily subcutaneously. Our conclusion is that the anti-atherosclerotic effect of calcium channel blockers is dose-dependent. It is not clear whether this effect takes place in the plasma compartment and/or in the intracellular compartment.