VASOPRESSIN PERFUSION WITHIN THE MEDIAL AMYGDALOID NUCLEUS ATTENUATES PROSTAGLANDIN FEVER IN THE URETHANE-ANESTHETIZED RAT

The antipyretic effect of arginine vasopressin (AVP) introduced into the ventral septal area (VSA) by push-pull perfusion was investigated in the urethane-anaesthetized rat. In addition, experiments were carried out to determine whether AVP could suppress fever when similarly perfused within the medial amygdaloid nucleus (meA). During push-pull perfusion of artificial cerebrospinal fluid within the VSA or meA, PGE1 injected intracerebroventricularly evoked fevers with respective magnitudes of 1.3 +/- 0.2-degrees-C and 1.4 +/- 0.3-degrees-C above baseline. Perfusion of AVP (6.5-mu-g/ml) within the VSA had significantly reduced the magnitude of PGE1 fever to 0.3 +/- 0.3-degrees-C above baseline, while having no significant effect on afebrile colonic temperature. Perfusion of AVP (6.5-mu-g/ml) within the meA had significantly attenuated the magnitude of PGE1 fever to 0.7 +/- 0.2-degrees-C above baseline, while having no significant effect on afebrile colonic temperature. These results support further the utility of the urethane-anaesthetized rat model for future investigations of the central control of fever and antipyresis. In addition, these data are consistent with the hypothesis that AVP may act within the meA as an endogenous antipyretic.