Effect of fusaric acid on the body temperature in spontaneously hypertensive and normotensive rats.

The effect of fusaric acid (FA) on the body temperature of age-matched spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto rats (WKY) was investigated at an ambient temperature of 4 degrees C. During a 7 h period of cold exposure the body temperature decreased by 6.5 degrees C in WKY (p less than 0.01) and by 5.4 degrees C in SR (p less than 0.05) after administration of 100 mg/kg FA, with the effects occurring faster in WKY. At 50 mg/kg the effect was lower. Naloxone completely abolished the temperature effect of FA in both rat strains. The naloxone antagonism may point to an opiate involvement in the thermoregulation after FA. A possible contribution of vasopressin and tetrahydroisoquinoline alkaloids to the maintenance of body temperature is also discussed.