Zhang X, Bean A J, Wiesenfeld-Hallin Z, Xu X J, Hökfelt T
Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
Neuroscience. 1995 Feb;64(4):893-915. doi: 10.1016/0306-4522(94)00452-b.
In this study co-localization of galanin- with calcitonin gene-related peptide (CGRP)-like immunoreactivity was examined in dorsal root ganglion neurons 14 days after sciatic nerve cut using a laser scanning confocal microscope. CGRP- and galanin-like immunoreactivities were also analysed in the dorsal horn of the spinal cord of these animals with immunofluorescence microscopy. The ultrastructural changes in galanin-immunoreactive, presumably primary afferent terminals in the superficial dorsal horn, were studied as well as the relationship between galanin-, substance P- and CGRP-like immunoreactivities in primary afferent terminals. Local galanin-positive neurons in lamina II were also analysed after peripheral axotomy. Under the confocal microscope, CGRP-like immunoreactivity was located in the perinuclear region, probably the Golgi complex, and in dot-like structures, probably representing large dense-core vesicles, in normal dorsal root ganglion neurons. However, after peripheral axotomy CGRP was mainly detected in dot-like structures. Only a slight decrease in percentage of CGRP neurons in dorsal root ganglion was seen after axotomy, and about 84% of the galanin-positive neurons contained CGRP. The field of galanin-positive nerve fibres in the superficial lumbar (L)4 and L5 dorsal horn expanded and the intensity of staining for CGRP was reduced in these regions 14 days after sciatic nerve cut. Using pre-embedding immunoelectron microscopy, several morphological changes were observed in galanin-positive terminals in laminae I and II ipsilateral to the lesion. Most importantly, the most frequently occurring type of galanin-positive terminals (type 1) showed distinct changes with a granular matrix, many immunoreactive, peripherally located large dense-core vesicles, empty large vesicles and synaptic vesicles which were displaced from the presynaptic zone. Other galanin-positive terminals underwent even more pronounced morphological changes, including extensive vesiculolysis, also of large dense-core vesicles, filamentous degeneration or formation of axonal labyrinths. An increased number of galanin-positive nerve terminals was observed in lamina III of the ipsilateral dorsal horn after axotomy. They did not form glomeruli and contained few large dense-core vesicles. Post-embedding immunocytochemistry combined with quantitative analysis revealed that significant changes occurred in a proportion of terminals also with regard to peptide content in large dense-core vesicles after axotomy. Thus, the percentage of galanin-positive large dense-core vesicles increased in several cases and that of substance P- and CGRP-immunoreactive ones decreased.(ABSTRACT TRUNCATED AT 400 WORDS)
在本研究中，使用激光扫描共聚焦显微镜，在坐骨神经切断14天后，检测背根神经节神经元中甘丙肽与降钙素基因相关肽（CGRP）样免疫反应性的共定位。还通过免疫荧光显微镜分析了这些动物脊髓背角中的CGRP和甘丙肽样免疫反应性。研究了浅背角中甘丙肽免疫反应性（推测为初级传入终末）的超微结构变化，以及初级传入终末中甘丙肽、P物质和CGRP样免疫反应性之间的关系。还分析了外周轴突切断后II层中局部甘丙肽阳性神经元的情况。在共聚焦显微镜下，正常背根神经节神经元中，CGRP样免疫反应性位于核周区域，可能是高尔基体复合体，以及点状结构中，可能代表大的致密核心囊泡。然而，外周轴突切断后，CGRP主要在点状结构中检测到。轴突切断后，背根神经节中CGRP神经元的百分比仅略有下降，约84%的甘丙肽阳性神经元含有CGRP。坐骨神经切断14天后，腰4和腰5浅背角中甘丙肽阳性神经纤维的区域扩大，这些区域中CGRP的染色强度降低。使用包埋前免疫电子显微镜，在损伤同侧的I层和II层中，甘丙肽阳性终末观察到几种形态学变化。最重要的是，最常见的甘丙肽阳性终末类型（1型）显示出明显变化，有颗粒状基质、许多免疫反应性的、位于周边的大致密核心囊泡、空的大囊泡和从突触前区移位的突触小泡。其他甘丙肽阳性终末经历了更明显的形态学变化，包括广泛的囊泡溶解，大致密核心囊泡也如此，丝状变性或轴突迷宫形成。轴突切断后，同侧背角III层中甘丙肽阳性神经终末数量增加。它们不形成小球，含有很少的大致密核心囊泡。包埋后免疫细胞化学结合定量分析显示，轴突切断后，一部分终末在大致密核心囊泡中的肽含量方面也发生了显著变化。因此，在几种情况下，甘丙肽阳性大致密核心囊泡的百分比增加，而P物质和CGRP免疫反应性囊泡的百分比降低。（摘要截断于400字）
