Failure of chloral hydrate to block the hypertonic saline induced changes in the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck

Abstract

Administration of chloral hydrate, 10 to 25 mg/animal/day, failed to block the appearance of the histological changes in the hypothalamic neurosecretory system (HNS) that normally follow daily administration of 1 ml of 3% NaCl solution. Since the histologic changes induced in the HNS by hypertonic saline are morphological manifestations of augmented secretion of antidiuretic hormone (ADH), the failure of chloral hydrate to block these changes in the HNS of the spotted owlet is suggestive of its failure to block ADH secretion. The failure of chloral hydrate to block the appearance of the hypertonic saline induced histological changes in the HNS contrasts with the ability of ethanol, reserpine and chlorpromazine to block the said changes in the HNS of the spotted owlet. The results suggest that in contrast to the situation prevailing in mammals, chloral hydrate does not exert an inhibitory influence on ADH secretion in birds.