Kuramoto H, Kato Y, Sakamoto H, Endo Y
Department of Applied Biology, Kyoto Institute of Technology, Japan.
Brain Res. 1996 Sep 23;734(1-2):186-92.
Galanin (GAL)-immunoreactive axon terminals on motor endplates of the esophageal striated muscles were demonstrated in mice, guinea-pigs and rats. The GAL-terminals innervated 33% of AChE-reactive motor endplates in mice and 6% of those in guinea-pigs. Double immunostaining revealed that separate GAL- and CGRP-positive terminals were localized within the same motor endplates in mice and rats. The GAL and CGRP terminals had different morphologies. No CGRP-immunoreactivity was found on motor endplates of the guinea-pig esophagus. Double immunostaining in rats showed that 68% of motor endplates with CGRP-nerve terminals were also supplied by GAL-nerve terminals, suggesting that the majority of esophageal striated muscles receive a dual innervation of GAL-and CGRP/ACh-containing terminals. By immuno-electronmicroscopy in the rat esophagus. GAL-immunoreaction was found in a small type of nerve terminals that possessed many large cored vesicles (90-130 nm) with intense immunoreaction. Larger GAL-negative nerve terminals with a cluster of small clear vesicle (40-50 nm), which seemed to be ACh-containing nerve terminals, were adjacent to a depression or slight protrusion of the sarcolemma and well-developed folds in the muscle fibers. At the motor endplates, the GAL-positive terminals made a synaptic contact via basement membrane with the sarcolemma of the muscle fibers, which was characterized by post-synaptic intense electron density. In most of all situations, in which the GAL-positive terminals and GAL-negative or -positive terminals were adjacent to each other and were also apposed to the striated muscles, the terminals were separated by attenuated sheet- or tongue-like cytoplasmic processes that appeared to originate from Schwann cells. Thus, the GAL-nerve terminals seem to provide a direct innervation of the striated muscle fibers rather than innervating the ACh-containing motor nerve terminals adjacent to the GAL-terminals.
在小鼠、豚鼠和大鼠的食管横纹肌运动终板上发现了加兰他敏（GAL）免疫反应性轴突终末。GAL终末支配小鼠33%的乙酰胆碱酯酶（AChE）反应性运动终板和豚鼠6%的此类终板。双重免疫染色显示，在小鼠和大鼠的同一运动终板内，GAL阳性终末和降钙素基因相关肽（CGRP）阳性终末是分开定位的。GAL和CGRP终末具有不同的形态。在豚鼠食管的运动终板上未发现CGRP免疫反应性。大鼠的双重免疫染色显示，68%有CGRP神经终末的运动终板也由GAL神经终末支配，这表明大多数食管横纹肌接受GAL和含CGRP/ACh终末的双重支配。通过对大鼠食管进行免疫电子显微镜检查发现，在一种小型神经终末中发现了GAL免疫反应，这种神经终末有许多大的有芯囊泡（90 - 130纳米），免疫反应强烈。较大的GAL阴性神经终末有一簇小的清亮囊泡（40 - 50纳米），似乎是含ACh的神经终末，它们与肌膜的凹陷或轻微突起以及肌纤维中发育良好的褶皱相邻。在运动终板处，GAL阳性终末通过基底膜与肌纤维的肌膜形成突触接触，其特征是突触后电子密度增强。在大多数情况下，GAL阳性终末与GAL阴性或阳性终末相互邻接且也与横纹肌并置，这些终末被似乎起源于施万细胞的变薄的片状或舌状细胞质突起分隔开。因此，GAL神经终末似乎直接支配横纹肌纤维，而不是支配与GAL终末相邻的含ACh的运动神经终末。
