Hurley Seth W, Arseth Heather A, Johnson Alan Kim
Department of Psychology & Neuroscience, University of North Carolina, Chapel Hill.
Department of Psychological and Brain Sciences, University of Iowa.
Behav Neurosci. 2018 Aug;132(4):284-292. doi: 10.1037/bne0000250. Epub 2018 Jun 28.
During extracellular dehydration, neural systems that sense deficits in body fluid homeostasis operate in tandem with those that mediate motivation and reward in order to promote ingestive behaviors that restore fluid balance. We hypothesized that hypothalamic orexin (Ox) neurons act as an interface to couple brain regions sensing and processing information about body fluid status with central nervous system motivation and reward systems. An initial set of anterograde and retrograde tracing experiments suggested that structures along the lamina terminalis (LT), a region of the forebrain that serves to monitor and integrate information reflecting body fluid balance, project to hypothalamic Ox neurons that, in turn, project to dopamine neurons in the ventral tegmental area (VTA). A second set of experiments determined whether Ox neuron activation is associated with extracellular dehydration and the seeking out and consumption of water and saline. An elevation of Fos-like immunoreactivity in Ox neurons was observed in fluid-depleted rats that were allowed to ingest water and sodium. A final experiment was conducted to determine whether Ox release in the VTA promotes thirst and salt appetite. Bilateral microinjection of the Ox Type I receptor antagonist SB-408124 into the VTA prior to acute extracellular dehydration attenuated fluid intake. Together, these studies support the hypothesis that structures along the LT modulate activity in the VTA through actions of orexinergic neurons that have cell bodies in the hypothalamus. This pathway may function to facilitate sustained consumption of fluids necessary for restoration of fluid balance. (PsycINFO Database Record
在细胞外脱水期间，感知体液稳态缺陷的神经系统与介导动机和奖赏的神经系统协同运作，以促进恢复体液平衡的摄食行为。我们假设下丘脑食欲素（Ox）神经元作为一个接口，将感知和处理体液状态信息的脑区与中枢神经系统的动机和奖赏系统联系起来。最初的一组顺行和逆行追踪实验表明，终板层（LT）沿线的结构（前脑的一个区域，用于监测和整合反映体液平衡的信息）投射到下丘脑的Ox神经元，而这些神经元又投射到腹侧被盖区（VTA）的多巴胺能神经元。第二组实验确定了Ox神经元的激活是否与细胞外脱水以及水和盐水的寻找与消耗有关。在允许摄入水和钠的脱水大鼠中，观察到Ox神经元中Fos样免疫反应性升高。进行了最后一项实验，以确定VTA中Ox的释放是否会促进口渴和盐食欲。在急性细胞外脱水之前，将Ox I型受体拮抗剂SB-408124双侧微量注射到VTA中，可减弱液体摄入。总之，这些研究支持了这样一种假设，即LT沿线的结构通过下丘脑中有细胞体的食欲素能神经元的作用来调节VTA中的活动。这条通路可能起到促进恢复体液平衡所需液体持续消耗的作用。（PsycINFO数据库记录）
