Effects of single cortical spreading depression on metabolic heat production in the rat

The effect of a single cortical spreading depression (CSD), elicited unilaterally by 10% KCI injection at the occipital cortex, was observed on the metabolic heat production in the rat with unilateral lesions in the preoptic and anterior hypothalamus (PO/AH). The metabolic rate increased by maximally 20% above its pre-CSD level for 7 min with a rise in rectal temperature when CSD entered the frontal cortex contralateral to the PO/AH lesion. By contrast, with the same onset, the increase in metabolic rate was lower (maximum 12%) and of shorter duration (3 min) in the ipsilateral CSD trial. Non-CSD trial with 0.9% NaCl injection had no effect on metabolic rate. The results provide further evidence to support the view that the frontal cortex of the rat is involved in the central thermoregulation.