Department of Molecular and Integrative Physiology, University of Michigan Ann Arbor, MI, USA.
Front Neurosci. 2013 Feb 22;7:19. doi: 10.3389/fnins.2013.00019. eCollection 2013.
Central proopiomelanocortin (POMC) neurons form a potent anorexigenic network, but our understanding of the integration of this hypothalamic circuit throughout the central nervous system (CNS) remains incomplete. POMC neurons extend projections along the rostrocaudal axis of the brain, and can signal with both POMC-derived peptides and fast amino acid neurotransmitters. Although recent experimental advances in circuit-level manipulation have been applied to POMC neurons, many pivotal questions still remain: how and where do POMC neurons integrate metabolic information? Under what conditions do POMC neurons release bioactive molecules throughout the CNS? Are GABA and glutamate or neuropeptides released from POMC neurons more crucial for modulating feeding and metabolism? Resolving the exact stoichiometry of signals evoked from POMC neurons under different metabolic conditions therefore remains an ongoing endeavor. In this review, we analyze the anatomical atlas of this network juxtaposed to the physiological signaling of POMC neurons both in vitro and in vivo. We also consider novel genetic tools to further characterize the function of the POMC circuit in vivo. Our goal is to synthesize a global view of the POMC network, and to highlight gaps that require further research to expand our knowledge on how these neurons modulate energy balance.
中枢前阿黑皮素原(POMC)神经元构成了强大的厌食网络,但我们对整个中枢神经系统(CNS)中该下丘脑回路的整合仍了解不足。POMC 神经元沿着大脑的前后轴延伸投射,并通过 POMC 衍生肽和快速氨基酸神经递质进行信号传递。尽管在回路水平操纵方面最近取得了实验进展,但仍有许多关键问题亟待解决:POMC 神经元如何以及在何处整合代谢信息?在什么条件下,POMC 神经元会在整个 CNS 中释放生物活性分子?GABA 和谷氨酸或 POMC 神经元释放的神经肽对于调节进食和代谢更为重要?因此,解析不同代谢条件下从 POMC 神经元中引出的信号的确切化学计量仍然是一项持续的努力。在这篇综述中,我们分析了该网络的解剖图谱,以及 POMC 神经元在体外和体内的生理信号。我们还考虑了新的遗传工具,以进一步在体内表征 POMC 回路的功能。我们的目标是综合 POMC 网络的全局视图,并突出需要进一步研究的空白领域,以扩展我们对这些神经元如何调节能量平衡的认识。