Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, MC H109, Hershey, PA 17033, USA.
Auton Neurosci. 2011 Apr 26;161(1-2):6-13. doi: 10.1016/j.autneu.2010.11.001. Epub 2010 Dec 13.
The afferent vagus transmits sensory information from the gastrointestinal (GI) tract and other viscera to the brainstem via a glutamatergic synapse at the level of the nucleus of the solitary tract (NTS). Second order NTS neurons integrate this sensory information with inputs from other CNS regions that regulate autonomic functions and homeostasis. Glutamatergic and GABAergic neurons are responsible for conveying the integrated response to other nuclei, including the adjacent dorsal motor nucleus of the vagus (DMV). The preganglionic neurons in the DMV are the source of the parasympathetic motor response back to the GI tract. The glutamatergic synapse between the NTS and DMV is unlikely to be tonically active in regulating gastric motility and tone although almost all neurotransmitters tested so far modulate transmission at this synapse. In contrast, the tonic inhibitory GABAergic input from the NTS to the DMV appears to be critical in setting the tone of gastric motility and, under basal conditions, is unaffected by many neurotransmitters or neurohormones. This review is based, in part, on a presentation by Dr Browning at the 2009 ISAN meeting in Sydney, Australia and discusses how neurohormones and macronutrients modulate glutamatergic transmission to NTS neurons and GABAergic transmission to DMV neurons in relation to sensory information that is received from the GI tract. These neurohormones and macronutrients appear to exert efficient "on-demand" control of the motor output from the DMV in response to ever-changing demands required to maintain homeostasis.
传入迷走神经通过孤束核（NTS）水平的谷氨酸能突触将来自胃肠道（GI）和其他内脏的感觉信息传递到脑干。第二级 NTS 神经元将这些感觉信息与来自调节自主功能和体内平衡的其他 CNS 区域的输入整合在一起。谷氨酸能和 GABA 能神经元负责将整合的反应传递到其他核，包括相邻的迷走神经背核（DMV）。DMV 中的节前神经元是回到胃肠道的副交感运动反应的来源。尽管迄今为止测试的几乎所有神经递质都调节这个突触的传递，但 NTS 和 DMV 之间的谷氨酸能突触不太可能在调节胃动力和张力方面持续活跃。相比之下，来自 NTS 到 DMV 的持续抑制性 GABA 能输入似乎对胃动力的张力至关重要，并且在基础条件下不受许多神经递质或神经激素的影响。这篇综述部分基于 Browning 博士在 2009 年澳大利亚悉尼举行的 ISAN 会议上的演讲，讨论了神经激素和宏量营养素如何调节谷氨酸能向 NTS 神经元的传递和 GABA 能向 DMV 神经元的传递，以及与从胃肠道接收的感觉信息有关。这些神经激素和宏量营养素似乎能够有效地“按需”控制 DMV 的运动输出，以响应维持体内平衡所需的不断变化的需求。
