Brain monoamines act through the prostaglandin release to influence the body temperature.

In the present study, the thermal responses induced by intraventicular administration of pyrogen prostaglandin E1, the brain monoamines norepinephrine and serotonin, and the antipyretic sodium acetylsalicylate (aspirin) were measured in conscious rabbits to assess the possible involvement of these substances in fever production. The body temperatures, metabolic rate, respiratory evaporative heat loss and vasomotor activity in response to the administration of these drugs were measured. The results showed that sodium acetylsalicylate, an inhibitor of prostaglandin synthetase, antagonizes the norepinephrine induced fever but not the prostaglandin fever. The data also showed that the serotonin induced hypothermia was reversed by prostaglandin administration. Thus, the fact strongly suggest that the prostaglandin E1 serves as a fever-prducing mediator in the central nervous system. Also, the norepinephrine fever and serotonin hpyothermia, respectively, may be associated with an increase and a decrease in prostaglandin synthesis in the brain.