PRENATAL COCAINE EXPOSURE AFFECTS THE DEVELOPMENT OF AORTIC ADRENERGIC-INNERVATION AND CONTRACTILE RESPONSES

This study examines the effects of prenatal cocaine administration on the development of vascular sympathetic innervation and contractile re sponsiveness. Rabbits received cocaine (4 mg/kg, iv, bid) or saline du ring gestational days 8 to 29. Aortas were obtained on postnatal days 10, 20, 30 and 50. Vascular smooth muscle responsiveness was assessed by measuring aortic contractile responses to norepinephrine (NE) and t o other vasoconstrictors. Vascular adrenergic innervation was evaluate d by measuring desipramine sensitive [H-3]-NE uptake into aortic ring segments and aortic NE content. [H-3]-NE uptake and NE content were re duced at postnatal days 10 and 20 in the rabbits exposed prenatally to cocaine. Differences were not observed at postnatal days 30 or 50. Th e contractile response to NE was reduced in rabbits exposed to cocaine prenatally. Maximal response and potency were decreased at postnatal day 10 and potency was still decreased at day 20, but not at the older ages. Contractile responses to serotonin (5-HT) and angiotensin II (A II) were not affected by prenatal cocaine exposure. These results sugg est that prenatal cocaine exposure delays the development of aortic ad renergic innervation and alpha adrenoceptor responsiveness.