orexinergi innervatiom of feeding-regulating neurons and signal transduction mechanism

我们研究了大鼠下丘脑中含食欲素神经元对摄食调节神经元的神经支配及其信号转导机制。食欲素阳性神经元分布于下丘脑外侧核和弓状核的投射轴突或轴突终末，其中神经肽Y(NPY)和前阿片黑素皮质素(POMC)阳性神经元位于弓状核。此外，含有食欲素的轴突终末也向结节乳头核中含有组胺的神经元进行突触输入。我们通过灌流系统研究了增食欲素在含NPY、POMC和组胺神经元中的信号转导机制。结果表明，食欲素通过G蛋白偶联机制激活含NPY和组胺的神经元，而抑制含POMC的神经元。这些结果可能表明，食欲素刺激NPY神经元，但抑制前额叶细胞，从而通过食欲素型L受体刺激摄食。增食欲素可能通过组胺神经元通过增食欲素2型受体发挥强烈的觉醒作用。

We have studied innervation of orexin-containing neurons on feeding-regulating neurons in the rat hypothalamus and signal transduction mechanism in these neurons. Orexin-containing neurons are distributed in the lateral hypothalamus and project axons or axon terminals in the arcuate nucleus (ARC) where Neuropeptide Y(NPY)- and Preopiomelanocortin (POMC)-containing neurons in the ARC. Moreover, orexin-containing axon terminals also make synaptic input to histamine-containing neurons in the tuberomammillary nucleus. We studied the signal transduction mechanism of orexin in the NPY-, POMC-, and histamine-containing neurons by perifusion system. The results have indicated that orexin activate NPY- and histamine-containing neurons while it inhibits POMC-containing neurons through G-protein coupling mechanisms. These results may indicate that orexin stimulates NPY neurons but inhibits POMC, thereby stimulating feeding via orexin type l receptor. Orexin may have a strong effect of awakening through histamine neurons via orexin type 2 receptor.