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

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。

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

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.