Abstract
Classic lesion and stimulation experiments has established areas in the brain that are involved in temperature regulation; heat loss center resides at the preoptic/anterior hypothalamic (PO/AH) area and heat conservation mechanism the posterior hypothalamus. However, since the time when temperature-sensitive neurone was found in the PO/AH area of dogs, it prevailed progressively with development of unit recording technique that temperature regulatory structure are widespread in the central nervous system, from diencephalon to spinal cord, and that stability of physiologic temperature regulation is achieved by means of a negative-feedback control system.
Studies on noradrenaline (NA) and 5-hydroxytryptamine (5-HT) systems, both of which are originated from nuclei in brain stem, made a great advances by Scandinavian investigaters and clarified gradually their relation to physiological function. According to amines theory which was proposed by FELDBERG and MYERS in 1963, NA and 5-HT play very important roles in thermoregulation, modifying the activity of the temperature-sensitive neurone in the PO/AH area, and then have a great influence on development of thermoregulatory responses.
Furthermore, it was clarified by us that a lot of warm-sensitive neurones localized in the raphe region of the midbrain and that although not all these are serotonergic neurones, the 5-HT system originated from the midbrain contains some axons of serotonergic neurones with high thermosensitivity. Hence, this indicates that the 5-HT system in the brain stem consists partly in thermoregulatory system and they works in couples. Based on the result that with an local administration of lysergic acid diethylamide (LSD) into the midbrain raphe region, blocking the action of serotonergic neurones, a rise in body temperature was induced, the 5-HT system works for responses to reduce body temperature in usual condition. With consideration of results mentioned above, it is possible to make an inferrence that circadien rhythm of body themperature may be due to diurnal changes of activation in the NA system and the 5-HT system of the brain stem. Activation state of the 5-HT system was determined in daytime and night by local injection of a given dose of LSD and predominant state of the action was verified in night. At present, a few studies has been focused on central mechanism of circadien rhythm of body temperature. So, the present paper has been not enough to satisfy a full explanation. More attentions should be paid for this subject in coming days.
