IMMUNOCYTOCHEMICAL LOCALIZATION OF GLUTAMATE DECARBOXYLASE IN RAT SPINAL-CORD
IMMUNOCYTOCHEMICAL LOCALIZATION OF GLUTAMATE DECARBOXYLASE IN RAT SPINAL-CORD
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DOI：
10.1002/cne.901640304
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发表时间：
1975-01-01
影响因子：
2.5
通讯作者：
WU, JY
中科院分区：
文献类型：
--
作者：
MCLAUGHLIN, BJ;BARBER, R;WU, JY
用过氧化物酶标记抗体技术，在光镜和电子显微镜下观察了谷氨酸脱羧酶(GAD)在大鼠腰骶段脊髓中的定位。光镜下可见GAD在背角I-III板层有较重的点状反应产物，在较深的背角IV-VI板层、中间灰质的内侧(VII板层)和中央管周围区域(X板层)也有中等强度的反应产物。GAD反应产物在脊髓腹角呈轻度分布，在运动神经元胞体上也可见点状沉积。光镜下观察到GAD反应产物在腹角和背角的点状分布，与电子显微镜观察到的脊髓灰质可比区域内含有GAD的突触终末相对应。在背角I-III层的GAD阳性终末比在IV-VI板更深的层更多。在背角含有GAD的终末与树突和细胞体突触前。在腹角运动核团中，GAD阳性的结节与大小树突和运动神经元胞体呈突触前联系。此外，含有GAD的小终末也与较大的轴突终末发生突触前反应，而较大的轴突终末又与运动神经元躯体发生突触前反应。GAD终末与背角和腹角的树突和胞体突触前反应的观察结果与GABA终末可能介导脊髓间神经元和运动神经元突触后抑制的证据相一致。在背角和运动核中，GAD阳性终末与其他轴突终末的突触前联系的额外发现与越来越多的证据一致，即GABA也可能是通过脊髓中的轴突突触介导突触前抑制的递质。
The GABA synthesizing enzyme, glutamate decarboxylase (GAD), has been localized by light and electron microscopy in the rat lumbosacral spinal cord using a peroxidase‐labeling antibody technique. The light microscopic localization shows heavy, punctate reaction product for GAD in the dorsal horn laminae I–III. Moderately heavy reaction product is also seen in the deeper dorsal horn laminae IV–VI, the medial aspect of the intermediate gray (lamina VII) and the region around the central canal (lamina X). A moderately light concentration of GAD reaction product is observed in the ventral horn, and punctate deposits of reaction product also are seen on motoneuron cell bodies.The punctate distribution of reaction product for GAD in both ventral and dorsal horns, as visualized by light microscopy, corresponds to GAD‐containing synaptic terminals seen by electron microscopy in comparable regions of the spinal gray. Many more GAD‐positive terminals are observed in dorsal horn laminae I–III than in deeper laminae IV–VI. GAD‐containing terminals in the dorsal horn are presynaptic to dendrites and cell bodies. GAD‐containing terminals presynaptic to other axon terminals are observed also, and they are more numerous in laminae II and III. In the ventral horn motor nuclei, GAD‐positive knobs are presynaptic to large and small dendrites and motoneuron cell bodies. In addition, small GAD‐containing terminals also are presynaptic to larger axonal terminals which are in turn presynaptic to motoneuron somata.The observation of GAD‐containing terminals presynaptic to dendrites and cell bodies in both dorsal and ventral horns is compatible with the evidence suggesting that GABA terminals may mediate postsynaptic inhibition of spinal interneurons and motoneurons. The additional finding of GAD‐positive terminals presynaptic to other axonal terminals in the dorsal horn and motor nuclei is consistent with the growing evidence that GABA also may be the transmitter mediating presynaptic inhibition via axo‐axonal synapses in the spinal cord.