Abstract Mkid 5

The sleep related changes in body temperature and the effects of environmental temperature on sleep, had given rise to the thought that the regulation of sleep and body temperature are intimately related. Another strong reason for this belief is the fact that the preoptic area which participates in the regulation of sleep is also considered as the main center for regulation of body temperature. Manipulations of the preoptic area temperature also alter sleep. The thermosensitive neurons of the preoptic area have been implicated not only in the regulation of body temperature but also of sleep. It was suggested that the thermoreceptors in the preoptic area may provide the input to the sleep-regulating mechanisms situated in this area. But the preoptic lesion and stimulation studies have shown that these regulations are controlled by independent, but overlapping neuronal mechanisms. The preoptic area could be playing an important role in fine-tuning the energy reserves, in which sleep and temperature regulations may be involved. The role of the preoptic area, in the inter-relationship between thermoregulatory and sleep regulatory mechanisms, which has given rise to the formulation of several hypotheses on sleep function, is addressed in this review.