THE EFFECTS OF RESERPINE ON VASOPRESSIN-CHOLESTEROL-INDUCED ATHEROMATOUS LESIONS

¹ Departments of Pharmacology and Toxicology and of Anatomy, University of Mississippi School of Medicine, Jackson, Mississippi

The effects of reserpine on vasopressin-cholesterol-induced atheromatous lesions in rabbits and on the calcium content of the vascular tissue of these animals were studied. The calcium content of rabbit aortae receiving vasopressin and cholesterol (8.57 ± 0.73 mEq of Ca⁺⁺/kg of fat-free dry wt.) was significantly higher (P < .001) than that of the aortae of rabbits receiving, in addition, reserpine (4.19 ± 0.41 mEq of Ca⁺⁺/kg of fat-free dry wt.). The aortae of normal rabbits contained 7.9 ± 0.77 mEq of Ca⁺⁺/kg of fat-free dry wt., whereas the aortae of rabbits receiving a standard pellet diet and vasopressin contained 7.02 ± 0.54 mEq of Ca⁺⁺/kg of fat-free dry wt. Both of these latter values are significantly higher (P < .01) than those of the group receiving a normal diet and treated with vasopressin and reserpine. Histologic results showed organized atheromatous plaques which contained large deposits of lipid material and traces of calcium within the intimal layer of the aortae of the vasopressin and cholesterol group. Some of the rabbits receiving vasopressin and cholesterol and additionally treated with reserpine had lesions, but these were less severe than those in the other groups. Rabbits on a normal diet receiving vasopressin or vasopressin and reserpine and rabbits receiving a normal diet showed no aortic lesions. These results indicate that reserpine has a vascular action in vivo affecting fat and calcium.