Li J L, Wang D, Kaneko T, Shigemoto R, Nomura S, Mizuno N
Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, People's Republic of China.
Neurosci Res. 2000 Apr;36(4):327-34. doi: 10.1016/s0168-0102(00)00095-x.
The synaptic relationship between substance P (SP) and its receptor, i.e. neurokinin-1 receptor (NK1R), was examined in the superficial laminae of the caudal subnucleus of the spinal trigeminal nucleus (medullary dorsal horn; MDH) of the rat. For confocal laser-scanning microscopy, double-immunofluorescence histochemistry for NK1 and SP was performed. In electron microscopic double-immunolabeling study, immunoreactivity for NK1R was detected with the silver-intensified gold method, while immunoreactivity for SP was detected with peroxidase immunohistochemistry. SP-immunoreactive axon terminals were observed to be in synaptic (mostly asymmetric) contact with NK1R-immunoreactive neuronal profiles in lamina I and lamina IIo. Although some SP-immunoreactive axon terminals were in synaptic contact with NK1R-immunoreactive sites of plasma membranes, NK1R-immunoreactivity was observed at both synaptic and non-synaptic sites of plasma membrane. Thus, SP released from axon terminals might not only act on NK1Rs facing the SP-containing axon terminals, but also diffuse in the extracellular fluid for distances larger than the synaptic cleft to act on NK1Rs at some distances from the synaptic sites.
在大鼠三叉神经脊束核尾侧亚核（延髓背角；MDH）的浅层中，研究了P物质（SP）与其受体即神经激肽-1受体（NK1R）之间的突触关系。对于共聚焦激光扫描显微镜检查，进行了NK1和SP的双重免疫荧光组织化学实验。在电子显微镜双重免疫标记研究中，用银增强金法检测NK1R的免疫反应性，而过氧化物酶免疫组织化学法检测SP的免疫反应性。在I层和IIo层中，观察到SP免疫反应性轴突终末与NK1R免疫反应性神经元轮廓形成突触（大多为不对称性）联系。虽然一些SP免疫反应性轴突终末与质膜的NK1R免疫反应性位点形成突触联系，但在质膜的突触和非突触位点均观察到NK1R免疫反应性。因此，从轴突终末释放的SP可能不仅作用于面对含SP轴突终末的NK1R，还可能在细胞外液中扩散超过突触间隙的距离，作用于距突触位点一定距离处的NK1R。
