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用双重免疫组织化学染色法,在光镜和电镜下观察了大鼠骶髓前角的胆碱能神经元与SP样末梢间的关系。胆碱能神经元被抗胆碱乙酰转移酶(ChAT)的单克隆抗体标记,用抗生物素—生物素技术,以β-半乳糖苷酶作为标记物,被吲哚-β-半乳糖苷(IbGa)反应产物染成蓝绿色。在同一切片上,SP样末梢被抗SP的多克隆抗体标记,用PAP技术,被DAB反应产物染成棕色。在光镜下,染成蓝绿色的ChAT样神经元和染成棕色的SP样纤维在前角出现。在电镜下,前角的ChAT样树突与SP样末梢之间,存在着许多不对称性的轴树突触(Gray Ⅰ型)、而几乎没有轴体突触和对称性的突触(Gray Ⅱ型)。这些结果显示骶髓前角的SP样终末与ChAT样运动神经元形成直接的突触,并提示这些突触主要是兴奋性的,对控制肌肉收缩有重要意义。
The relationship between cholinergic neurons and SP-like endings in rat sacral anterior horn was observed under light and electron microscopes by double immunohistochemical staining. Cholinergic neurons are labeled with a monoclonal antibody to anticholinergic acetyltransferase (ChAT) using anti-biotin-biotin technology, beta-galactosidase as a marker, and indole-beta-galactoside (IbGa) reaction product dyed blue-green. On the same section, the SP-like tips were labeled with anti-SP polyclonal antibody and stained brown with DAB reaction product using PAP technique. Under light microscopy, cyan-like ChAT-like neurons and brown-stained SP-like fibers appeared at the anterior horn. Under electron microscopy, there are many asymmetric axial dendrites (Gray Ⅰ) between the anterior horn of the ChAT-like dendrites and the SP-like extremities, whereas there is almost no synaptic and symmetrical synapses (Gray Ⅱ type). These results show that SP-like terminals of sacral anterior horn form direct synapses with ChAT-like motor neurons and suggest that these synapses are primarily excitatory and important for controlling muscle contractions.