Mitchell Caitlin S, Begg Denovan P
School of Psychology, UNSW Sydney, Sydney, NSW, Australia.
J Neuroendocrinol. 2021 Apr;33(4):e12952. doi: 10.1111/jne.12952. Epub 2021 Mar 3.
Food intake and energy expenditure are regulated by peripheral signals providing feedback on nutrient status and adiposity to the central nervous system. One of these signals is the pancreatic hormone, insulin. Unlike peripheral administration of insulin, which often causes weight gain, central administration of insulin leads to a reduction in food intake and body weight when administered long-term. This is a result of feedback processes in regions of the brain that regulate food intake. Within the hypothalamus, the arcuate nucleus (ARC) contains subpopulations of neurones that produce orexinergic neuropeptides agouti-related peptide (AgRP)/neuropeptide Y (NPY) and anorexigenic neuropeptides, pro-opiomelanocortin (POMC)/cocaine- and amphetamine-regulated transcript (CART). Intracerebroventricular infusion of insulin down-regulates the expression of AgRP/NPY at the same time as up-regulating expression of POMC/CART. Recent evidence suggests that insulin activity within the amygdala may play an important role in regulating energy balance. Insulin infusion into the central nucleus of the amygdala (CeA) can decrease food intake, possibly by modulating activity of NPY and other neurone subpopulations. Insulin signalling within the CeA can also influence stress-induced obesity. Overall, it is evident that the CeA is a critical target for insulin signalling and the regulation of energy balance.
食物摄入和能量消耗受外周信号调节，这些信号向中枢神经系统反馈营养状况和肥胖程度。其中一种信号是胰腺激素胰岛素。与外周注射胰岛素通常会导致体重增加不同，长期中枢注射胰岛素会导致食物摄入量和体重下降。这是调节食物摄入的脑区中反馈过程的结果。在下丘脑中，弓状核（ARC）包含产生促食欲神经肽刺鼠相关肽（AgRP）/神经肽Y（NPY）的神经元亚群以及厌食神经肽阿黑皮素原（POMC）/可卡因和苯丙胺调节转录物（CART）。脑室内注入胰岛素会下调AgRP/NPY的表达，同时上调POMC/CART的表达。最近的证据表明，杏仁核内的胰岛素活性可能在调节能量平衡中起重要作用。向杏仁核中央核（CeA）注入胰岛素可以减少食物摄入，可能是通过调节NPY和其他神经元亚群的活性来实现的。CeA内的胰岛素信号传导也会影响应激诱导的肥胖。总体而言，很明显CeA是胰岛素信号传导和能量平衡调节的关键靶点。
