Water intoxication death following hypothalamic lesions in the rat

Rats received large, bilateral lesions of the ventromedial hypothalamus. Water or saline intakes, urine outputs and body temperatures were observed for up to 24 hr after surgery. Fifty percent of the operated animals drank excessively and died within 4-6 hr when permitted access to water. Urine outputs were low and symptoms of water intoxication were evident. When allowed access to saline, outputs rose and the number of animals which survived increased as the saline concentration increased. Body temperatures approached 40 degrees C during drinking, but did not differ from operated animals which refused to drink. It was concluded that the deposition of metallic ions strongly stimulates a hypothalamic drinking system which results in overhydration and water intoxication death.