P物质与Griffonia simplicifolia I-B_4结合位点在大鼠初级传入神经元的共存

THE CO-LOCALIZATION OF SUBSTANCE P AND THE BINDING SITES OF IFFONIA SIMPLICIFOLIA LB. IN THE PRIMARY AFFERENT NEURONS OF THE RAT

应用荧光双标组织化学技术观察到，在大鼠腰段脊神经节中，GriffoniasimplicifoliaI-B.（I-B4）结合反应物与P物质样免疫反应物均分布在小细胞中，且34％～43％的I-B4结合反应阳性细胞和87％～95％的P物质阳性细胞为I-B4与P物质双标细胞。切断单侧脊神经后根的大鼠，切断侧脊髓后角内I-B4结合反应在术后第3d即明显减弱，至第5d消失。向成年大鼠蛛网膜下腔注射辣椒素后，脊髓后角和Lissauer束内的I-B4结合反应于第3d已明显减弱，于第5d、第7d和第10d减弱更显著，但仍有部分残留。电镜下.脊髓后角I～III层有大量轴突终末被I-B4标记，其中许多标记终末参与构成突触小球。在包埋前免疫金-银-ABC法双标电镜标本上，脊髓后角内I-B4与SP双标轴突终末分别占I-B4阳性轴突终未总数和P物质阳性轴突终末总数的33％～36％和39％～53％。上述结果进一步证实了I-B4与初级传入的小神经元结合的特异性，并表明I-B4结合位点是鉴别脊髓后角内P物质阳性轴突终末的初级传入来源的重要标志。

By using double fluorescence histochemistry. it was found that, in the lumbar spinal ganglion, the binding of Griffonia simplicifolia I-B4(I-B4) and substance p-like immunoreactivity (SP-LI) were limited to the small-diameter primary afferent neurones and that 34%～43% of the total I-B4-binding positive neurones and 87%～95% of the SP-LI neurons were double-labelled with I-B4 and SP. After unilateral rhizotomy, the I-B4-binding in the superficial layers of the spinal dorsal horn on the side ipsilateral to the operation was markedly weakened on day 3 after the operation and disappeared on day 5 after the operation.In the adult rats to which capsaicin was intrathecally injected, the I-B4-binding in the spinal dorsal horn and Lissauer's tract was obviously reduced on day 3 after capsaicin treatment. on day 5, 7 and 10 after the capsaicin treatment, the I-B4-binding was highly decreased but not disappeared. Under electron microscope, a lot of axon terminals in laminae I～III, of the spinal dorsal horn were labelled with I-B4, many of the labelled terminals joining to form synaptic glomeruli. In the electron microscopic double labelling preparations by means of pre-embedding immunogold silver-ABC method, the axonic terminals double-labelled with I-B4 and SP constituted 33～36% of the total I-B4 positive axon terminals and 39～53% of the total SP positive axon terminals,respectively. The above results further demonstrated the specificity that I-B4 binds to the small-diameter primary afferent neuron and indicated that the binding site may be used as an important marker for indentifying the primary afferent origin of SP-ergic axonic terminal in the dorsal horn of the spinal cord.