Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan.
Neuropeptides. 2010 Apr;44(2):133-8. doi: 10.1016/j.npep.2009.11.010. Epub 2009 Dec 24.
Ghrelin, an n-octanoylated 28-amino acid brain-gut peptide, was first isolated from extracts of porcine stomach. Ghrelin is an endogenous ligand for the growth hormone secretagogue type 1a receptor (GHS-R1a), the functionally active form of GHS-R, and stimulates feeding and growth hormone secretion. Ghrelin is mainly produced in the A/X-like cells of the oxyntic glands of the stomach and is the main orexigenic circulating hormone that acts on the hypothalamus to affect feeding behavior and energy metabolism. Ghrelin-containing neuronal cell bodies are localized in the hypothalamic arcuate nucleus, a center that integrates signals for energy homeostasis. Ghrelin-containing nerve fibers are widely distributed in the brain. Accumulated evidence shows that hypothalamic neuropeptides such as neuropeptide Y (NPY), orexin and proopiomelanocortin (POMC) are involved in the regulation of feeding behavior and energy homeostasis via neuronal circuits in the hypothalamus. Ghrelin also forms part of the feeding-regulating neuronal circuitry in conjunction with other feeding-regulating peptide-containing neurons within the hypothalamus. In view of the fact that one decade has now passed since ghrelin was first discovered, we review advances that have been made in ghrelin research during that time and how this has impacted on our knowledge of feeding regulation in the hypothalamus. We also summarize our current understanding of the neuronal interactions between ghrelin and the different kinds of feeding-regulating peptide-containing neurons in the hypothalamus based on evidence at the ultrastructural level.
胃饥饿素是一种 N-辛酰基化的 28 个氨基酸的脑肠肽，最初从猪胃提取物中分离得到。胃饥饿素是生长激素促分泌素受体 1a（GHS-R1a）的内源性配体，GHS-R 的功能活性形式，它刺激摄食和生长激素分泌。胃饥饿素主要在胃的泌酸腺 A/X 样细胞中产生，是作用于下丘脑影响摄食行为和能量代谢的主要食欲素循环激素。含有胃饥饿素的神经元胞体位于下丘脑弓状核，这是一个整合能量稳态信号的中心。含有胃饥饿素的神经纤维广泛分布于大脑中。大量证据表明，下丘脑神经肽如神经肽 Y（NPY）、食欲素和促黑细胞皮质素原（POMC）通过下丘脑神经元回路参与摄食行为和能量稳态的调节。胃饥饿素还与下丘脑内其他含有摄食调节肽的神经元一起，构成摄食调节神经元回路的一部分。鉴于胃饥饿素最初被发现已经过去了十年，我们回顾了在此期间胃饥饿素研究取得的进展，以及这些进展如何影响我们对下丘脑摄食调节的认识。我们还根据超微结构水平的证据，总结了我们目前对下丘脑内胃饥饿素与不同种类的摄食调节肽含能神经元之间的神经元相互作用的理解。
