Hyper-running activity originating from the hypothalamus : An element of instinctive behaviors

我们发现，兴奋下丘脑腹内侧核(VNM)的神经元诱导了刻板印象的超速跑，这与攻击或逃跑的动机无关。这种跑步活动被认为是本能行为的主要要素之一。然后假定伴随着跑步活动的是陈旧的代谢变化。本研究探讨了VMH诱发超速跑和改变糖代谢的神经机制，发现VMH内注射聚合物凝胶可以诱导超速跑。这可能是由于在凝胶中加入GABA不能诱导跑步活动，从而解除了对GABA能抑制神经元系统的抑制。向VMH内注射海人藻酸也可引起超速跑，这种作用不被GABA阻断。这些结果表明，作用于VMH的海人酸受体的神经兴奋性氨基酸在诱发Junning活动中起生理学作用，这种氨基酸的释放受到GABA能神经元的突触前抑制。向VMH注射海人藻酸可增加血浆皮质酮、肾上腺素、去甲肾上腺素和葡萄糖的水平，并诱导超速跑。这表明，VMH中的海人酸受体也参与了维持跑步活动所需的代谢变化。本研究还表明，VMH诱导的跑步活动涉及通过髓状小体和中脑中央灰质的神经元通路，VMH的神经元输出影响昼夜运动活动。

We found that excitation of neurons in the ventromedial nucleus of the hypothalamus(VNM)induced stereotyped hyper-running, which was not associated with the motivation of an attack or escape. Such running activity is regarded as one of the principal elements of instinctive behaviors. Then it is presumed that stereotyped metabolic changes accompany the running activity. In this study, neurnal mechanisms in the VMH involved in inducing the hyper-running and in changing glucose metabolism were investigated.The injection of polymer-gel into the VMH was shown to induce the hyper-running. This was probably due to disinhibition of the GABAergic inhibitory neuronal system, since inclusion of GABA in the gel failed to induce the running activity. Injection of kainate into the VMH also induced the hyper-running ; the effect of kainate was not blocked by GABA. These findings suggest that neuroexcitatory amino acids acting at the kainate receptor in the VMH play a physiological role in inducing Junning activity and that the release of such amino acids are presynaptically inhibited by GABAergic neurons.Injection of kainate into the VMH increased plasma levels of corticosterone, epinephrine, norepinephrine and glucose, as well as inducing the hyper-running. This suggests that kainate receptors in the VMH are also involved in evoking metabolic changes required to maintain running activity.It is also suggested in the present study that the neuronal pathway via the marmmillary body and the midbrain central gray is involved in the VMH-inducing running activity and that neuronal output from the VMH affects the circadian locomotor activity.