Pharmacologic Control of Temperature Regulation

During the past two decades the physiology and pharmacology of thermoregulation have been the subjects of a considerable volume of research and numerous books and reviews. The physiologic aspects have been reviewed in detail most recently by Cabanac (1). The effects of drugs on temperature regulation have been discussed at two symposia, which resulted in books containing the proceedings (2, 3), and a third symposium in this series was held in Banff in September 1976. In reviewing this prodigious development of knowledge of the subject, any demarcation of these reports into pharmacologic is somewhat arbitrary since in many cases drugs have been used as tools to elucidate physiologic mechanisms. With respect to the actions of drugs on central thermoregulatory mechanisms, many of the compounds studied affect the CNS by modifying the activity of the several neuronal pathways that impinge on the central thermostats or that mediate the effector responses controlling body temperature. The role of the putative neuro­ transmitters involved constitutes perhaps the most debatable topic in thermoregula­ tion (4). Because there has been no recent exhaustive review of this subject we restrict the present discussion to the role of these neuroamines and the effects of drugs on their activity in the CNS. A convenient model on which to base a discussion of the role of amines in thermoregulation is the neural net described by Carlson (5). He divided the system into afferent, central, and efferent components. Of these three components there is little or no evidence for a role of amines in the afferent sensory division. Conversely there is good evidence for a role of amines in the peripheral effector part of the neural net; its pharmacology is easy to analyze and is well understood. The central compo-