Local effects of papaverine on normal, atherosclerotic, and vasospastic carotid arteries of rabbits: an experimental study

Objective: Papaverine is a direct-acting vasodilating agent that is frequently used in the treatment of vasospasm after subarachnoid hemorrhage. However, not much knowledge is available about the effect of papaverine on atherosclerotic vessels.Material and Methods: Twenty-four New Zealand-type male rabbits were divided into 4 groups: normal, atherosclerotic, normal vasospastic, and atherosclerotic vasospastic vessels. The atherosclerotic groups (2 and 4) were fed with high cholesterol diet and the other groups with a normal diet for 4 weeks. Cholesterol levels were measured before and after exposure to these diets. In groups 3 and 4, a vasospasm model for common carotid arteries was established. In all subjects, papaverine was applied topically on the left common carotid artery (study subgroups a) and serum physiologic on the right (control subgroups b). Before and 10, 20, 30, 40, 50, and 60 minutes after topical application, vessel diameter was measured and compared between the groups. Histological evaluation of the artery was also performed in all subjects.Results: In the atherosclerosis groups (Groups 2 and 4), blood cholesterol levels were significantly higher after 4 weeks of high cholesterol diet. Atherosclerosis and vasospasm development were confirmed with histological examination in the respective groups. Papaverine application lead to significant dilation in all groups according to the SF application. Its most prominent vasodilating effect was seen in normal vessels, while its effect gradually decreased from groups 2 to 4.Conclusions: The vasodilating effect of papaverine decreased in the presence of atherosclerosis. New experimental and clinical studies are required to determine the effective local papaverine doses in atherosclerotic cases.