Mechanism of protection from atherosclerosis by verapamil in the cholesterol-fed rabbit

Seventy-two rabbits were separated into groups to receive no drug, subcutaneous verapamil, metoprolol, hydralazine, metoprolol and hydralazine, or oral verapamil in 1 of 3 doses daily for 10 weeks. They also received a high-cholesterol diet and had serum triglyceride, cholesterol, and verapamil levels measured twice during the study. Blood pressure (BP), heart rate and weight were measured every 10 days. Approximately 60% of the rabbits given verapamil had detectable levels of the drug in their serum. This group had significantly less severe atherosclerosis in their aortas at the time they were killed, even though they had significantly higher cholesterol levels than the other groups. This group also did not have different BP than the other groups (except for the subcutaneous verapamil group). Thus, protection from atherosclerosis by verapamil in the cholesterol-fed rabbit is not the result of lowering of BP.