CEREBRAL-CORTEX DOES NOT MODULATE REGULATED DECREASE IN CORE TEMPERATURE DURING HYPOXEMIA IN RATS

In newborns and adults of a number of species including humans, exposu re to acute hypoxemia produces a ''regulated'' decease in core tempera ture, the mechanism of which is unknown. Considering that various cort ical areas participate in autonomic regulation including thermoregulat ion, the present experiments were carried out to test the hypothesis t hat the cerebral cortex plays a role in modulating the regulated decre ase in core temperature during acute hyperemia. This hypothesis was te sted by determining the core temperature response to acute hypoxemia i n chronically instrumented adult Sprague-Dawley rats before and after cortical spreading depression (i.e., functional decortication) was pro duced by the local application of potassium chloride to the dura overl ying the cerebral hemispheres. There was no effect of cortical spreadi ng depression on baseline core temperature. Core temperature decreased during acute hyperemia in a similar fashion when the cerebral cortex was intact as well as during functional decortication. Thus our data d o not support the hypothesis that the cerebral cortex modulates the re gulated decrease in core temperature that occurs in adult rats during acute hypoxemia.