Analysis of hypothalamic network for thermoregulation.

体温由包括下丘脑在内的中枢神经系统控制。几乎没有关于体温调节网络的知识，这使得直接将电生理和药理学数据与在整个动物中观察到的体温调节反应联系起来是困难的。本研究旨在回答这一问题。首先，为了研究左右两侧大脑如何共同控制颤抖，将氯胺酮麻醉的大鼠植入双侧视前区，并将单侧下丘脑正尾侧横断至下丘脑前部，切断ROSTO-尾侧方向的纤维。单侧视前加温可抑制双侧冷致寒战，但切断侧加温对寒战无明显影响。因此，左右视前区之间似乎没有信息交换来控制颤抖。当部分横断覆盖下丘脑外侧部分(内侧前脑束)时，横断与单侧横断整个下丘脑具有相同的效果。因此，颤抖的传出信号通过内侧前脑束下行。在第二个实验中，在单侧热刺激或电刺激视前区时，皮肤血管扩张发生在双侧(Kanosue等，1991)。在接受与颤抖实验类似的单侧下丘脑切断的大鼠中，单侧视前加温不仅在完整侧，而且在切断侧都对后爪产生双侧血管扩张。因此，控制体温调节血管运动的信息--不同于控制颤抖的信息--跨越视前区的中线。用于血管运动控制的传出纤维似乎通过内侧前脑束下降。

The body temperature is controlled by the central nervous system including the hypothalamus. There is almost no knowledge of thermoregulatory "network" , which makes it difficult to link electrophysiological and pharmachological data directly with thermoregulatory responses observed in whole animals. Present study was pland to answer this question. First, to examine how the control of shivering is shared between the brain's right and left sides, ketamine anesthetized rats had been implanted thermodes on both sides of the preoptic area and received unilateral transection of the hypothalamus just caudal to the anterior hypothalamus, which severed fibers running rosto-caudal diretion. Unilateral preoptic warming on the intact side produced bilateral suppression of cold-induced shivering without predominance of either side of the body but warming on the transected side had no effect on shivering. Therefore, no information seems to be exchanged between the left and right preoptic aera for control of shivering. When a partial transection covered the lateral part of the hypothalamus (the medial forebrain bundle), the transection had the same effect as did unilateral transections of the whole hyporhalamus. Efferent signals for shivering, thus, descend through the medial forebrain bundle. In the second experiment, skin vasodilation occurs bilaterally during unilateral thermal or electrical stimulation of the preoptic area (Kanosue et al., 1991). In rats which had received similar unilateral transection of the hypothalamus as in the shivering experiment, unilateral preoptic warming not only on the intact side but also on the transected side produced bilateral vasodilation on the hind paw. Therefore, information coutrolling thermoregulatory vasomotion--unlike that controlling shivering--crosses the midline within the preoptic area. Efferent fibers for vasomotor control seem to decend through the medial forebrain bundle.