Role of adrenergic system in thermoglycemic response in baby rabbits

¹ Department of Physiology and Nutrition, Bengal Veterinary College, Calcutta, India

Baby albino rabbits housed at 32°C were subjected to an ambient temperature of 42°C and 45°C for a period of 2 1/2 hours. They showed a rise of rectal temperature from 38.0° to 39.0° and 39.4°, respectively; a tachycardia from 235 to 318 and 365, respectively. However, there was no significant change in blood composition, such as erythrocyte or leukocyte count, specific gravity of blood or the hematocrit reading of the ear vein blood. These rabbits showed an increase of blood sugar level from normal 68.5 mg/100 ml blood to 98.7 and 115.1 mg, respectively. This thermoglycemic response is common in birds and has been demonstrated here also in baby rabbits. This response was abolished by the ganglion-blocking agent, pentamethylene-1,5-bis (1-methylpyrrolidinium) hydrogen tartrate and also by the adrenergic blocking agent, ergotamine tartrate. It is concluded that the thermoglycemic response, hyperthermia and tachycardia are mediated by the adrenergic system and are probably evidence of defective thermoregulatory power in baby rabbits.