Sensitivity of hypothalamic sites to salicylate and prostaglandin

This study was designed to determine the dose of salicylate necessary to produce substantial antipyresis, and to determine the relationship between the response to salicylate and prostaglandin infused into the same region of the preoptic area of the rabbit. The effect of preoptic infusions of three doses of sodium salicylate, or a control solution, on the fever produced by an intravenous injection of endogenous pyrogen was measured. The pyrogenic response to prostaglandin E1 injected into the same preoptic sites in the same rabbits was also monitored. The results showed that the 50 microgram/microL per hour dose of salicylate did not produce significant antipyresis but that the 100 and 200 microgram/microL per hour doses did. The results also showed a significant correlation between the magnitude of fever produced by prostaglandin E1 and the magnitude of antipyresis produced by sodium salicylate at a particular site. Those sites at which infusion of salicylate produced the most effective antipyresis were also the ones at which prostaglandin E1 produced the largest fevers.