The antipyretic activity of adenosine agonists

1. Thermoregulatory reactions after IV administration of A1 [N6-cyclohexyladenosine (CHA); 0.15 mg/kg] and A2 [5'-N-ethylcarboxamidoadenosine (NECA); 0.15 mg/kg] receptor agonists were investigated in pyrogen-treated rabbits (lipopolysaccharide; 1 microgram/kg IV) at an ambient temperature of 20 +/- 1 degrees C. 2. Both compounds produced antipyresis, which was accompanied by inhibition of metabolic rate. NECA, additionally, reversed the inhibitory effect of pyrogen on respiratory rate. 3. Neither CHA nor NECA affected postpyrogen drops in ear skin temperature. 4. The mechanisms underlying the antipyretic action of the compounds in question are discussed.