REDUCTION OF REGIONAL CEREBRAL BLOOD-FLOW BY MELATONIN IN YOUNG-RATS

MELATONIN (10 ng) was subcutaneously administered to 14-day-old Spragu e-Dawley rats. Regional blood flow (rCBF) was measured in 22 anatomica lly defined structures 20 min later using iodo[C-14]antipyrine and qua ntitative autoradiography. rCBF was markedly reduced in the cerebral a reas supplied by circle of Willis and the basilar arteries. Melatonin also significantly decreased blood flow to choroid plexuses. These fin dings suggest that circulating melatonin may contribute to regulation of cerebral blood flow and brain fluid balance.