Changes in rectal temperature of the rabbit by intracerebroventricular injection of bradykinin and related kinins.

The effects of intracerebrovascular injections of bradykinin (BK), lysyl-bradykinin (L-BK), methionyl-lysyl-bradykinin (ML-BK) and des-arginyl-bradykinin (Des-Arg9-BK) on the rectal temperature of rabbits were investigated. A linear dose-response curve could be obtained with bradykinin. Equimolar doses to BK of L-BK and ML-BK gave responses of the rectal temperature undistinguishable from those of BK. In contrast, the smaller polypeptide Des-Arg9-BK did not show any hyperthermic properties. Since prostaglandins (PG) are known to potentiate (facilitate) the peripheral effects of BK and display a hyperthermic action, their synthesis being inhibited by antipyretics, we studied the effect of indomethacin and paracetamol on the BK-induced rise in rectal temperature in rabbits. It could be shown that these drugs inhibited partially the response to BK. The possible participation of BK in thermoregulation will be discussed.