Polypneic Panting in Anesthetized Gats

Abstract

In a recent series of experiments a region of the cat's brain was found which responded to local heating by acceleration of respiration, panting and in some instances by the appearance of sweat on the foot pads. 1 These experiments were performed on anesthetized animals and we wish here to consider the use of anesthesia in such work.

Six experiments were performed under light nembutal anesthesia (18 mg. per kilo) with unsatisfactory results. Respiration under nembutal is slow and heating the whole animal does not lead to polypnea and panting until an abnormally high body temperature is reached. In 6 experiments the animals were prepared under ether by the insertion of a pair of electrodes into the brains and, 3 to 4 hours later, with the animals in the waking condition, heating the brain induced good polypneic panting in 3 cases, which indicates that previous etherization is not detrimental to the response. Two cats panted at a rapid rate during recovery from the anesthesia although their rectal temperatures were only 36.2°C. and 37.6°C. respectively.

Urethane does not depress respiration like nembutal, and was employed with good results in 41 experiments in a usual dosage of 1 gm. per kilo intraperitoneally. Urethane anesthesia has the disadvantage, however, of being associated in some cats with a period of polypnea and panting which may occur at a normal body temperature with no apparent external causation.

In the 41 experiments under urethane, polypneic panting in cats with relatively low rectal temperatures was encountered as a more or less initial feature in 1.5 cases. Eight of these 15 animals had received supplementary ether during the operative preparation and 4 had had a heating pad on during this procedure.