Abstract：
Melanin-concentrating hormone (MCH) cells in the hypothalamus regulate fundamental physiological functions like energy balance, sleep, and reproduction. This diversity may be ascribed to the neurochemical heterogeneity among MCH cells. One prominent subpopulation of MCH cells coexpresses cocaine- and amphetamine-regulated transcript (CART), and as MCH and CART can have opposing actions, MCH/CART+ and MCH/CART- cells may differentially modulate behavioral outcomes. However, it is not known if there are differences in the cellular properties underlying their functional differences; thus, we compared the neuroanatomical, electrophysiological, and morphological properties of MCH cells in male and female Mch-cre;L10-Egfp reporter mice. Half of MCH cells expressed CART and were most prominent in the medial hypothalamus. Whole-cell patch-clamp recordings revealed differences in their passive and active membrane properties in a sex-dependent manner. Female MCH/CART+ cells had lower input resistances, but male cells largely differed in their firing properties. All MCH cells increased firing when stimulated, but their firing frequency decreases with sustained stimulation. MCH/CART+ cells showed stronger spike rate adaptation than MCH/CART- cells. The kinetics of excitatory events at MCH cells also differed by cell type, as the rising rate of excitatory events was slower at MCH/CART+ cells. By reconstructing the dendritic arborization of our recorded cells, we found no sex differences, but male MCH/CART+ cells had less dendritic length and fewer branch points. Overall, distinctions in topographical division and cellular properties between MCH cells add to their heterogeneity and help elucidate their response to stimuli or effect on modulating their respective neural networks.
摘要：
黑色素浓缩激素（MCH）细胞在下丘脑调节基本的生理功能，如能量平衡，睡眠,和繁殖。这种多样性可能归因于MCH细胞之间的神经化学异质性。MCH细胞的一个突出的亚群共表达可卡因和苯丙胺调节的转录物（CART），由于MCH和CART可以有相反的行动，MCH/CART+和MCH/CART-细胞可差异调节行为结果。然而,尚不清楚其功能差异背后的细胞特性是否存在差异；因此，我们比较了神经解剖学，电生理学,和MCH细胞在雄性和雌性Mch-cre中的形态特性；L10-Egfp报告小鼠。一半的MCH细胞表达CART，在下丘脑内侧最突出。全细胞膜片钳记录显示其被动和主动膜特性以性别依赖性方式存在差异。雌性MCH/CART+细胞具有较低的输入电阻，但是雄性细胞的发光特性大不相同。所有MCH细胞在刺激时都会增加放电，但是他们的发射频率随着持续的刺激而降低。MCH/CART+细胞表现出比MCH/CART-细胞更强的刺速适应。MCH细胞兴奋性事件的动力学也因细胞类型而异，MCH/CART+细胞的兴奋性事件上升速度较慢。通过重建我们记录的细胞的树突状树干，我们没有发现性别差异,但是男性MCH/CART+细胞的树突长度和分支点更少。总的来说,MCH细胞之间的地形划分和细胞特性的区别增加了它们的异质性，并有助于阐明它们对刺激的反应或对调节各自神经网络的影响。
