Effects of Chlorpromazine and Autonomic Nervous System Blocking Agents in Combating Heat Stress

The effects of autonomic blocking agents were studied on the survival rate of adrenalectomized rats exposed to 37.5°–38.5°C for 6 hours. Thorazine increased the survival rate of heat-stressed adrenalectomized rats, its effect being enhanced by addition of subeffective doses of hydrocortisone. Pendiomide ditartrate was ineffective when given alone, but was protective when added to subeffective doses of hydrocortisone. Dibenamine, Regitine and Pro-Banthine appeared to be detrimental under the experimental conditions employed. The mechanism underlying the protective effects of Thorazine and Pendiomide apparently does not involve body temperature control. The observations suggest that the mechanisms of protection against heat and cold exposure differ from those involved in protection against other types of stress.