Hypothermic effect of sodium acetysalicylate on afebrile monkeys.

1 Afebrile monkeys (Macaca cyclopis) receiving systemic (100-300 mg/kg, i.p.) or central (5-20 mg into the 3rd cerebral ventricle) administration of sodium acetylsalicylate showed a dose-dependent reduction in rectal temperature in a thermoneutral environment (25 degrees C).2 Administration of sodium acetylsalicylate (10 mg) into the 3rd cerebral ventricle produced a hypothermia with a temperature decrement of 1.0 degrees C, ehile an intraperitoneal injection of 300 mg/kg was required for a temperature decrement of 0.9 degrees C. The ratio between the total doses given by the two toutes was 1 to 120.3 Following the administration of sodium acetylsalicylate, a decline in rectal temperature was accompanied by a tail cutaneous vasodilatation.4 The data suggest that sodium acetylsalicylate can lower the normal body temperature by activating heat loss or decreasing the normal (tonic) inhibition of the heat loss mechanism via the central nervous system.