The effect of N6-cyclohexyladenosine and 5'-N-ethylcarboxamidoadenosine on body temperature in normothermic rabbits

1. Thermal responses to i.v. administration of N6-cyclohexyladenosine (CHA; 0.15 mg/kg), A1 adenosine receptor agonist, or 5'-N-ethylcarboxamidoadenosine (NECA; 0.15 mg/kg), A2 adenosine receptor agonist, were investigated in normothermic rabbits at an ambient temperature (Ta) of 20.0 +/- 1.0 degrees C. 2. Although both compounds inhibited metabolic heat production, only NECA produced hypothermia. 3. NECA showed strong hypotensive activity. 4. Both compounds produced vasoconstriction of the ear skin vessels and CHA, in addition, slowed down the respiratory rate. 5. The role of A1 or A2 adenosine receptors in the thermoregulatory activity of these compounds is discussed.