Reserpine inhibition of hypertonic saline induced changes in the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck

Abstract

The effects of reserpine on the histology of the HNS in the spotted owlet, Athene brama, which was treated with hypertonic saline, were investigated. Reserpine, 25-30 μg/animal/day, completely blocked the appearance of the histological changes in the HNS that normally follow daily treatment with 1 ml of 3% NaCl solution. The histological picture of the HNS of reserpine treated birds was identical with that of the HNS of normal birds, indicating the effectiveness of the drug in inhibiting the hypertonic saline induced histological changes in the HNS. Since the histological changes that are induced in the HNS by hypertonic saline are presumably indicative of increased secretion of ADH, the results are interpreted as providing histological evidence in favor of the concept that reserpine exerts an inhibitory effect on ADH secretion. It is suggested that the effect of reserpine on ADH secretion in birds is comparable to that reported in the case of mammals. The probable pathways involved in the reserpine induced inhibition of antidiuresis are discussed.