Powley Terry L, Hudson Cherie N, McAdams Jennifer L, Baronowsky Elizabeth A, Phillips Robert J
Department of Psychological Sciences, Purdue University, West Lafayette, Indiana, 47907-2081.
J Comp Neurol. 2016 Mar 1;524(4):713-37. doi: 10.1002/cne.23892. Epub 2015 Oct 13.
The fundamental roles that the stomach plays in ingestion and digestion notwithstanding, little morphological information is available on vagal intramuscular arrays (IMAs), the afferents that innervate gastric smooth muscle. To characterize IMAs better, rats were given injections of dextran biotin in the nodose ganglia, and, after tracer transport, stomach whole mounts were collected. Specimens were processed for avidin-biotin permanent labeling, and subsets of the whole mounts were immunohistochemically processed for c-Kit or stained with cuprolinic blue. IMAs (n = 184) were digitized for morphometry and mapping. Throughout the gastric muscle wall, IMAs possessed common phenotypic features. Each IMA was generated by a parent neurite arborizing extensively, forming an array of multiple (mean = 212) branches averaging 193 µm in length. These branches paralleled, and coursed in apposition with, bundles of muscle fibers and interstitial cells of Cajal. Individual arrays averaged 4.3 mm in length and innervated volumes of muscle sheet, presumptive receptive fields, averaging 0.1 mm(3) . Evaluated by region and by muscle sheet, IMAs displayed architectural adaptations to the different loci. A subset (32%) of circular muscle IMAs issued specialized polymorphic collaterals to myenteric ganglia, and a subset (41%) of antral longitudinal muscle IMAs formed specialized net endings associated with the serosal boundary. IMAs were concentrated in regional patterns that correlated with the unique biomechanical adaptations of the stomach, specifically proximal stomach reservoir functions and antral emptying operations. Overall, the structural adaptations and distributions of the IMAs were consonant with the hypothesized stretch receptor roles of the afferents.
尽管胃在摄入和消化过程中发挥着重要作用，但关于支配胃平滑肌的迷走神经肌内排列（IMA），即传入神经，的形态学信息却很少。为了更好地描述IMA，给大鼠的结节神经节注射葡聚糖生物素，在示踪剂运输后，收集胃全层标本。对标本进行抗生物素蛋白-生物素永久标记处理，对全层标本的子集进行免疫组织化学处理以检测c-Kit或用铜蓝染色。对184个IMA进行数字化处理以进行形态测量和绘图。在整个胃肌壁中，IMA具有共同的表型特征。每个IMA由一个广泛分支的母神经突产生，形成多个（平均 = 212个）平均长度为193μm的分支阵列。这些分支与肌纤维束和 Cajal间质细胞平行并与之并列。单个阵列平均长度为4.3mm，支配的肌层体积即假定的感受野平均为0.1mm³。按区域和肌层评估，IMA显示出对不同位点的结构适应性。环形肌IMA的一个子集（32%）向肌间神经节发出特殊的多形性侧支，胃窦纵行肌IMA的一个子集（41%）形成与浆膜边界相关的特殊网状终末。IMA以与胃独特的生物力学适应性相关的区域模式集中分布，特别是胃近端的储存功能和胃窦的排空操作。总体而言，IMA的结构适应性和分布与传入神经的假定牵张感受器作用一致。
