Thermoregulatory response to hypoxia after inhibition of the central heme oxygenase–carbon monoxide pathway

Abstract (1) Centrally acting carbon monoxide (CO) seems to play thermoregulatory actions, but no report exists about its role in hypoxia-induced anapyrexia. (2) CO arises from the catabolism of heme by heme oxygenase (HO), an enzyme that is overexpressed during hypoxia. Thus, we tested the hypothesis that the central HO–CO pathway modulates hypoxia-induced anapyrexia by means of intracerebroventricular injection of the HO inhibitor ZnDPBG. (3) Core temperature ( T C ) of awake rats was determined by biotelemetry. ZnDPBG did not alter basal T c , but it exacerbated hypoxia-induced anapyrexia, indicating that the central HO–CO pathway is a modulator of hypoxia-induced anapyrexia, probably preventing excessive decreases in T c .