Anteroventral third ventricle lesion suppresses fever, but not stress-induced hyperthermia in rats

Body core temperature (Tco) of unrestrained rats was monitored to compare the effects of electrolytic lesion of the anteroventral third ventricle (AV3V) region on stress-induced hyperthermia or lipopolysaccharide (LPS)-induced fever. We found that stress-induced hyperthermia was not significantly reduced by AV3V lesion, whereas pyrogen-induced fever was significantly lower in rats in which the lesion completely ablated the organum vasculosum laminae terminalis (OVLT), located in the AV3V region. The results indicate that although the central neural elements producing both stress- and pyrogen-induced elevations in Tco may be prostaglandin related, stress hyperthermia is not activated by mechanisms in the OVLT region, as is fever induced by LPS.