INTERLEUKIN-1 RECEPTOR ANTAGONIST INCREASES SURVIVAL IN RAT HEATSTROKE BY REDUCING HYPOTHALAMIC SEROTONIN RELEASE

During onset of heatstroke, rats displayed higher values of hypothalam ic serotonin release and score of hypothalamic neuronal damage, and lo wer values of mean arterial pressure and hypothalamic blood flow compa red with normothermic control rats. In another group in which interleu kin-1 receptor antagonist (IL-1 ra; 200 mu g/kg, i.v.) was injected 30 or 60 min after the start of heat exposure, the augmented hypothalami c serotonin release, diminished hypothalamic blood flow, arterial hypo tension and hypothalamic neuronal damage during heatstroke were reduce d as compared to the saline control group. The survival time (interval between onset of heatstroke and death) of the heatstroke rats was pro longed by treatment with IL-1 ra. The data indicate that IL-1 ra incre ases survival during rat heatstroke by reducing hypothalamic serotonin release.