Perfusion of vasopressin within the ventral septum of the rabbit suppresses endotoxin fever.

The antipyretic action of arginine vasopressin (AVP), administered into a lateral cerebral ventricle or directly into the brain tissue via push-pull perfusion, was investigated in conscious New Zealand White rabbits. Administration of AVP into a lateral cerebral ventricle (ICV) was ineffective in reducing an endotoxin-induced fever and did not alter body temperature in the afebrile rabbit. Control push-pull perfusions with the carrier vehicle were without effect on endotoxin fevers or normal body temperature. Perfusion of the vehicle containing AVP provided significant antipyretic activity against both intravenous (IV) and ICV endotoxin without affecting normal body temperature. Both the maximum fever height and the fever index were significantly reduced during AVP perfusion. Tissue sites in which AVP was found to be antipyretic were located in the rostroventral parts of the septal region, at sites similar to those where perfusion of the peptide caused antipyresis in the sheep and rat. These results support the hypothesis that AVP, or a closely related molecule, may modulate fever within the central nervous system.