Musings on the wanderer: What's new in our understanding of vago-vagal reflex? IV. Current concepts of vagal efferent projections to the gut
Musings on the wanderer: What's new in our understanding of vago-vagal reflex? IV. Current concepts of vagal efferent projections to the gut
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DOI：
10.1152/ajpgi.00478.2002
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发表时间：
2003-03-01
影响因子：
4.5
通讯作者：
Goyal, RK
中科院分区：
文献类型：
--
作者：
Chang, HY;Mashimo, H;Goyal, RK
迷走神经传出神经由不同的下运动和节前副交感神经纤维组成，构成迷走神经介导反射的运动肢。迷走神经下运动神经元（LMN）起源于疑核，介导涉及内脏横纹肌的反射。LMN为运动终板提供胆碱能神经支配，运动终板被肌间氮能神经元抑制。来自运动背核的节前神经元执行副交感神经运动和分泌功能。胆碱能节前神经元形成通向平滑肌内脏的平行的抑制性和兴奋性迷走神经通路，并通过烟碱和毒蕈碱受体刺激节后神经元。反过来，节后抑制性神经元释放ATP，VIP和NO，而兴奋性神经元释放ACh和P物质。迷走神经运动效应依赖于内脏的内在运动活性和抑制性和兴奋性迷走神经影响之间的相互作用。这些相互作用有助于解释食管扩张、胃动力、下食管括约肌和幽门括约肌的生理学。迷走神经分泌途径主要是兴奋性的，涉及ACh和VIP作为节后兴奋性神经递质。迷走神经对分泌功能的影响可以直接发挥，也可以通过释放局部介质或循环激素发挥。
Vagal efferents, consisting of distinct lower motor and preganglionic parasympathetic fibers, constitute the motor limb of vagally mediated reflexes. Arising from the nucleus ambiguus, vagal lower motor neurons (LMN) mediate reflexes involving striated muscles of the orad gut. LMNs provide cholinergic innervation to motor end plates that are inhibited by myenteric nitrergic neurons. Preganglionic neurons from the dorsal motor nucleus implement parasympathetic motor and secretory functions. Cholinergic preganglionic neurons form parallel inhibitory and excitatory vagal pathways to smooth muscle viscera and stimulate postganglionic neurons via nicotinic and muscarinic receptors. In turn, the postganglionic inhibitory neurons release ATP, VIP, and NO, whereas the excitatory neurons release ACh and substance P. Vagal motor effects are dependent on the viscera's intrinsic motor activity and the interaction between the inhibitory and excitatory vagal influences. These interactions help to explain the physiology of esophageal peristalsis, gastric motility, lower esophageal sphincter, and pyloric sphincter. Vagal secretory pathways are predominantly excitatory and involve ACh and VIP as the postganglionic excitatory neurotransmitters. Vagal effects on secretory functions are exerted either directly or via release of local mediators or circulating hormones.