MECHANISMS OF THERMAL RESPONSES TO PENTYLENETETRAZOL

¹ Department of Pharmacology and Therapeutics, University of Manitoba Faculty of Medicine, Winnipeg

Pentylenetetrazol given in repeated convulsant doses to dogs completely paralyzed with a neuromuscular blocking agent produced a consistent hyperthermia at ambient temperatures above a critical range of 23 to 25°C, and a consistent hypothermia at lower temperatures. Increased cutaneous blood flow, with resulting loss of body heat, appears to be the major factor in the hypothermic response to pentylenetetrazol, whereas increased heat production, independent of skeletal muscle activity, appears to be the major factor in the hyperthermic response to the drug. Experiments on dogs with the spinal cord acutely sectioned at C₄ to C₆ indicate that the thermal responses to pentylenetetrazol are of central origin, but are not simply the result of an induced poikilothermia.