Helke C J, Charlton C G, Wiley R G
Neuroscience. 1986 Oct;19(2):523-33. doi: 10.1016/0306-4522(86)90278-2.
Substance P-immunoreactivity and specific substance P binding sites are present in the spinal cord. Receptor autoradiography showed the discrete localization of substance P binding sites in both sensory and motor regions of the spinal cord and functional studies suggested an important role for substance P receptor activation in autonomic outflow, nociception, respiration and somatic motor function. In the current studies, we investigated the cellular localization of substance P binding sites in rat spinal cord using light microscopic autoradiography combined with several lesioning techniques. Unilateral injections of the suicide transport agent, ricin, into the superior cervical ganglion reduced substance P binding and cholinesterase-stained preganglionic sympathetic neurons in the intermediolateral cell column. However, unilateral electrolytic lesions of ventral medullary substance P neurons which project to the intermediolateral cell column did not alter the density of substance P binding in the intermediolateral cell column. Likewise, 6-hydroxydopamine and 5,7-dihydroxytryptamine, which destroy noradrenergic and serotonergic nerve terminals, did not reduce the substance P binding in the intermediolateral cell column. It appears, therefore, that the substance P binding sites are located postsynaptically on preganglionic sympathetic neurons rather than presynaptically on substance P-immunoreactive processes (i.e. as autoreceptors) or on monoamine nerve terminals. Unilateral injections of ricin into the phrenic nerve resulted in the unilateral destruction of phrenic motor neurons in the cervical spinal cord and caused a marked reduction in the substance P binding in the nucleus. Likewise, sciatic nerve injections of ricin caused a loss of associated motor neurons in the lateral portion of the ventral horn of the lumbar spinal cord and a reduction in the substance P binding. Sciatic nerve injections of ricin also destroyed afferent nerves of the associated dorsal root ganglia and increased the density of substance P binding in the dorsal horn. Capsaicin, which destroys small diameter primary sensory neurons, similarly increased the substance P binding in the dorsal horn. These studies show that the cellular localization of substance P binding sites can be determined by analysis of changes in substance P binding to discrete regions of spinal cord after selective lesions of specific groups of neurons. The data show the presence of substance P binding sites on preganglionic sympathetic neurons in the intermediolateral cell column and on somatic motor neurons in the ventral horn, including the phrenic motor nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)
P物质免疫反应性和特异性P物质结合位点存在于脊髓中。受体放射自显影显示P物质结合位点在脊髓的感觉和运动区域均有离散定位，功能研究表明P物质受体激活在自主神经传出、痛觉、呼吸和躯体运动功能中起重要作用。在当前研究中，我们使用光学显微镜放射自显影结合多种损伤技术，研究了大鼠脊髓中P物质结合位点的细胞定位。向上颈神经节单侧注射自杀转运剂蓖麻毒素，可减少中间外侧细胞柱中P物质结合以及胆碱酯酶染色的节前交感神经元。然而，向中间外侧细胞柱投射的延髓腹侧P物质神经元的单侧电解损伤，并未改变中间外侧细胞柱中P物质结合的密度。同样，破坏去甲肾上腺素能和5-羟色胺能神经末梢的6-羟基多巴胺和5,7-二羟基色胺，也未降低中间外侧细胞柱中P物质的结合。因此，似乎P物质结合位点位于节前交感神经元的突触后，而非位于P物质免疫反应性过程（即作为自身受体）或单胺能神经末梢的突触前。向膈神经单侧注射蓖麻毒素导致颈脊髓膈运动神经元单侧破坏，并使该核团中P物质结合显著减少。同样，向坐骨神经注射蓖麻毒素导致腰脊髓腹角外侧部分相关运动神经元丧失，以及P物质结合减少。向坐骨神经注射蓖麻毒素还破坏了相关背根神经节的传入神经，并增加了背角中P物质结合的密度。辣椒素可破坏小直径初级感觉神经元，同样增加了背角中P物质的结合。这些研究表明，通过分析特定神经元群选择性损伤后脊髓离散区域P物质结合的变化，可以确定P物质结合位点的细胞定位。数据显示中间外侧细胞柱中的节前交感神经元以及腹角中的躯体运动神经元（包括膈运动核）上存在P物质结合位点。（摘要截选至400字）
