Human Physiology, Medical Bioscience, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.
Department of Surgery, Flinders Medical Centre, Adelaide, SA, Australia.
Neurogastroenterol Motil. 2019 Oct;31(10):e13685. doi: 10.1111/nmo.13685. Epub 2019 Jul 29.
The enteric nervous system contains inhibitory and excitatory motor neurons which modulate smooth muscle contractility. Cell bodies of longitudinal muscle motor neurons have not been identified in human intestine.
We used retrograde tracing ex vivo with DiI, with multiple labeling immunohistochemistry, to characterize motor neurons innervating tenial and inter-tenial longitudinal muscle of human colon.
The most abundant immunohistochemical markers in the tertiary plexus were vesicular acetylcholine transporter, nitric oxide synthase (NOS), and vasoactive intestinal polypeptide (VIP). Of retrogradely traced motor neurons innervating inter-tenial longitudinal muscle, 95% were located within 6mm oral or anal to the DiI application site. Excitatory motor neuron cell bodies, immunoreactive for choline acetyltransferase (ChAT), were clustered aborally, whereas NOS-immunoreactive cell bodies were distributed either side of the DiI application site. Motor neurons had small cell bodies, averaging 438 + 18µm in cross-sectional area, similar for ChAT- and NOS-immunoreactive subtypes. Motor neurons innervating the tenia had slightly longer axial projections, with 95% located within 9mm. ChAT-immunoreactive excitatory motor neurons to tenia were clustered aborally, whereas NOS-immunoreactive inhibitory motor neurons had both ascending and descending projections. VIP immunoreactivity was rarely present without NOS immunoreactivity in motor neurons.
Tenial and inter-tenial motor neurons innervating the longitudinal muscle have short projections. Inhibitory motor neurons have less polarized projections than cholinergic excitatory motor neurons. Longitudinal and circular muscle layers are innervated by distinct local populations of excitatory and inhibitory motor neurons. A population of human enteric neurons that contribute significantly to colonic motility has been characterized.
肠神经系统包含抑制性和兴奋性运动神经元，它们调节平滑肌的收缩性。人类肠内的纵行肌运动神经元胞体尚未被鉴定。
我们使用 DiI 逆行示踪术，结合多重标记免疫组织化学，来描述支配人结肠间肌和间肌纵行肌的运动神经元。
三级神经丛中最丰富的免疫组织化学标志物是囊泡乙酰胆碱转运体、一氧化氮合酶（NOS）和血管活性肠肽（VIP）。在支配间肌纵行肌的逆行追踪运动神经元中，95%位于 DiI 应用部位口侧或肛侧 6mm 以内。胆碱乙酰转移酶（ChAT）免疫反应性兴奋性运动神经元细胞体聚集在远侧，而 NOS 免疫反应性细胞体分布在 DiI 应用部位的两侧。运动神经元的细胞体较小，横截面积平均为 438±18µm，ChAT 和 NOS 免疫反应性亚型相似。支配腱的运动神经元的轴突投影稍长，95%位于 9mm 以内。腱的 ChAT 免疫反应性兴奋性运动神经元聚集在远侧，而 NOS 免疫反应性抑制性运动神经元既有升支又有降支。在运动神经元中，VIP 免疫反应性很少存在而没有 NOS 免疫反应性。
支配纵行肌的腱和间肌运动神经元具有短的投射。抑制性运动神经元的投射比胆碱能兴奋性运动神经元更不极化。纵行和环形肌层由不同的局部兴奋性和抑制性运动神经元支配。已经描述了一种对结肠运动有重要贡献的人类肠神经元群体。
