THE EFFECT OF RESERPINE ON VASCULAR TISSUE SODIUM AND POTASSIUM CONTENT

¹ Departments of Pharmacology and Toxicology and Medicine, University of Mississppi Medical Center, Jackson, Mississippi

Dog femoral artery sodium decreased 43%, potassium 20% and water 11% after administration of 0.3 mg/kg of reserpine 24 and 48 hr before. Rabbit aortic sodium fell 40%, potassium 30% and water 10% after 3 mg/kg of reserpine 24 and 48 hr before. Changes were significant. Six hours after 5 mg/kg of reserpine, rat aortic tissue sodium fell 7% and potassium 8% ; 66 hr later sodium had fallen 18% and the potassium 12%. After two doses of 5 mg/kg of reserpine (48 and 72 hr), the sodium fell 31% and the potassium 30%. There were no changes in rat tissue water. Femoral vessels perfused with Tyrode's solution took up sodium (from 220 ± 3 to 558 ± 49 mEq/kg) whereas they suffered a loss of potassium (from 97.9 ± 3.9 to 42 ± 6 mEq/kg). When norepinephrine was added to the perfusate (1 µ/ml), 42% of the sodium uptake was prevented whereas further loss of potassium (to 31 ± 2 mEq/kg) occurred. Supersensitivity was demonstrated in the rabbits and rats receiving reserpine. Hypotension after reserpine occurred in the dog, rabbit and rat; however, it persisted for 72 hr in the dog and rabbit, but only 6 hr in the rat. The results indicate a possible involvement of electrolytes in the development of supersensitivity but not in the hypotension which occurs after reserpine.