Hypothalamic Temperature in Unanesthetized Albino Rats during Feeding and Sleeping.

ABRAMS, ROBERT, AND H. T. HAMMEL. Hypothalamic temperature in unanesthetized albino rats during feeding and sleeping. Am. J Physiol. 206(3) : 641-646. Ig64.-Stainless steel and polyethylene reentrant tubes were implanted permanently in the brain and abdominal cavity of male albino rats. Thermocouples were placed in the tubes and the leads were counterweighted over the rat cage. Temperatures were recorded continuously for up to 4 hr in unanesthetized, unrestrained rats. A decrease in temperature of the preoptic area usually accompanied sleep. Feeding was consistently associated with a rapid increase in the temperature of the preoptic area, piriform cortex, and abdominal cavity. A significant increase in metabolic rate occurred simultaneously with the rise in temperature of the preoptic region. The caloric content of the diet was not important in determining the degree of temperature rise. The activity associated with eating was postulated to account for the increase in brain and other body temperatures.