Discussion of Cerebral Tryptamine Receptors: Functional Considerations

Abstract

Publisher Summary The chapter discusses some kinetic studies on the effect of environmental temperature on the turnover rate of brain 5-HT and catecholamines. Exposure of rats to an environmental temperature of 38°C produces a 24° rise in rectal temperature, accompanied by an increase in the turnover rate of brain 5-HT. This increase in turnover rate begins within 2 hours and reaches a maximum of 71% above normal after 14 hours. Pretreatment with 100 mg/kg of p-chlorophenylalanine for 3 days blocks the rise in brain 5-HIAA and markedly increases the toxicity of the 38°C environment. In contrast to the brain, there is no change in turnover rate of 5-HT in the duodenum at 38°C. The turnover rate of brain (NE), measured from the decline of endogenous levels after administration of α-methyltyrosine is increased by cold exposure. A maximal increase in synthesis of 66% occurs after 2 hours at 4°C, and the turnover rate gradually returns to normal over the next 48 hours of cold exposure.