Colonic afferent input and dorsal horn neuron activation differs between the thoracolumbar and lumbosacral spinal cord
Colonic afferent input and dorsal horn neuron activation differs between the thoracolumbar and lumbosacral spinal cord
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DOI：
10.1152/ajpgi.00013.2019
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发表时间：
2019-09-01
影响因子：
4.5
通讯作者：
Brierley, Stuart M.
中科院分区：
文献类型：
--
作者：
Harrington, Andrea M.;Caraballo, Sonia Garcia;Brierley, Stuart M.
远端结肠由内脏神经和盆神经支配。分别中继到胸腰段和腰骶段脊髓。虽然这些通路中的结肠传入神经的外周特性已得到很好的研究，但它们进入脊髓的输入仍然不明确。从结肠壁和内腔的双重逆行追踪，结合体内结直肠扩张和磷酸化MAPK ERK 1/2（PERK）的脊髓神经元激活标记，使我们能够识别处理结肠传入输入的胸腰段和腰骶段脊髓回路。在胸腰段背角，结肠传入神经的中央投射主要标记从结肠壁和本地化在椎板I和V。从腔和壁追踪中识别出腰骶部投射，存在于各种背角板层、侧支束和背侧灰质连合中。无害的在体内结直肠扩张引起显着的神经元激活（pERK免疫反应）在腰骶部背角，但不是在胸腰椎地区。然而，有害的体内结直肠扩张引起显着的神经元激活在胸腰段和腰骶段背角，与激活的神经元的分布相关的跟踪投影的模式。结直肠扩张激活的背角神经元根据其神经化学被鉴定为投射神经元或兴奋性和抑制性中间神经元的可能群体。我们的研究结果表明，如何在内脏和骨盆通路的结肠传入差异中继机械感觉信息到脊髓和脊髓通路处理非伤害性和伤害性stimulation.NEW和值得注意的招聘作出贡献在小鼠中，逆行追踪从结肠壁和管腔被用来确定独特的传入神经元和脊髓背角内的中央投射的人口。我们发现，有显着的差异，脊髓区域之间的结肠传入中枢投射的分布模式和背角神经元激活的结肠直肠扩张引起的模式。这些研究结果表明，结肠传入输入如何影响结肠机械感觉的脊髓处理。
The distal colon is innervated by the splanchnic and pelvic nerves. which relay into the thoracolumbar and lumbosacral spinal cord, respectively. Although the peripheral properties of the colonic afferent nerves within these pathways are well studied, their input into the spinal cord remain ill defined. The use of dual retrograde tracing from the colon wall and lumen, in conjunction with in vivo colorectal distension and spinal neuronal activation labeling with phosphorylated MAPK ERK 1/2 (PERK), allowed us to identify thoracolumbar and lumbosacral spinal cord circuits processing colonic afferent input. In the thoracolumbar dorsal horn, central projections of colonic afferents were primarily labeled from the wall of the colon and localized in laminae I and V. In contrast. lumbosacral projections were identified from both lumen and wall tracing, present within various dorsal horn laminae, collateral tracts, and the dorsal gray commissure. Nonnoxious in vivo colorectal distension evoked significant neuronal activation (pERK-immunoreactivity) within the lumbosacral dorsal horn but not in thoracolumbar regions. However, noxious in vivo colorectal distension evoked significant neuronal activation in both the thoracolumbar and lumbosacral dorsal horn, with the distribution of activated neurons correlating to the pattern of traced projections. Dorsal horn neurons activated by colorectal distension were identified as possible populations of projection neurons or excitatory and inhibitory interneurons based on their neurochemistry. Our findings demonstrate how colonic afferents in splanchnic and pelvic pathways differentially relay mechanosensory information into the spinal cord and contribute to the recruitment of spinal cord pathways processing non-noxious and noxious stimuli.NEW & NOTEWORTHY In mice, retrograde tracing from the colon wall and lumen was used to identify unique populations of afferent neurons and central projections within the spinal cord dorsal horn. We show that there are pronounced differences between the spinal cord regions in the distribution pattern of colonic afferent central projections and the pattern of dorsal horn neuron activation evoked by colorectal distension. These findings demonstrate how colonic afferent input influences spinal processing of colonic mechanosensation.