Effects of adenosine 3',5'-cyclic monophosphate on thermoregulation in both rats and rabbits

The effects of intraventricular administration of dibutyryl adenosine 3',5'-cyclic monophosphate (db cyclic AMP) on the thermoregulatory responses of unanesthetized rats and rabbits to different ambient temperatures (Ta) were assessed. Administration of db cyclic AMP (10-60 mM) produced dose-dependent hypothermia in both rats and rabbits at Ta 2-22 degrees C. The hypothermia in response to db cyclic AMP was due to decreased metabolic heat production and cutaneous vasodilatation. There was no change in respiratory evaporative heat loss. In contrast, in the heat (30-32 degrees C), db cyclic AMP administration produced dose-dependent hyperthermia in these animals. The hyperthermia was due to increased metabolism (due to muscular shivering) and decreased heat losses. The reduction in heat losses was shown by a decrease in both cutaneous circulation and respiratory evaporative heat loss. The data demonstrate that the thermoregulatory responses induced by central administration of db cyclic AMP are Ta-dependent.