Pollock R, Kerr R, Maxwell D J
Laboratory of Human Anatomy, Institute of Biomedical and Life Sciences, University of Glasgow, UK.
Brain Res. 1997 Nov 28;777(1-2):22-30. doi: 10.1016/s0006-8993(97)00965-7.
The relationship between substance P-containing axons and sympathetic preganglionic neurons possessing the neurokinin-1 receptor was investigated in the lateral horn of the rat thoracic spinal cord. Sympathetic preganglionic neurons were labelled retrogradely with Fluorogold. Sections containing labelled cells were reacted with antibodies against choline acetyltransferase, substance P and the neurokinin-1 receptor and examined with three-colour confocal laser scanning microscopy. In all, 95 sympathetic preganglionic neurons were examined and 79% of these were immunoreactive for the neurokinin-1 receptor. Substance P-immunoreactive axons not only made contacts with preganglionic neurons which were immunoreactive for the receptor but also made contacts with cells which did not express the receptor. Dendrites, labelled with immunoreactivity for choline actyltransferase, also received contacts from substance P-immunoreactive varicosities but this was not related to the presence or the absence of receptor. An electron microscopic analysis was performed to investigate the relationship between substance P-containing boutons and dendrites possessing the neurokinin-1 receptor. Immunoreactivity for substance P was detected with peroxidase immunocytochemistry and immunoreactivity for the receptor was detected with the silver-intensified gold method. Substance P-containing boutons made synapses with dendrites which were positively and negatively labelled for the receptor. Receptor immunoreactivity was not usually present at synapses formed by substance P boutons with neurokinin-1-immunoreactive dendrites. It is concluded that substance P may modulate much of the activity of sympathetic preganglionic neurons through an indirect non-synaptic mechanism.
在大鼠胸段脊髓侧角，研究了含P物质的轴突与具有神经激肽-1受体的交感神经节前神经元之间的关系。用荧光金逆行标记交感神经节前神经元。将含有标记细胞的切片与抗胆碱乙酰转移酶、P物质和神经激肽-1受体的抗体反应，并用三色共聚焦激光扫描显微镜检查。总共检查了95个交感神经节前神经元，其中79%对神经激肽-1受体呈免疫反应性。P物质免疫反应性轴突不仅与对该受体呈免疫反应性的节前神经元接触，也与不表达该受体的细胞接触。用胆碱乙酰转移酶免疫反应性标记的树突也接受P物质免疫反应性膨体的接触，但这与受体的有无无关。进行电子显微镜分析以研究含P物质的终扣与具有神经激肽-1受体的树突之间的关系。用过氧化物酶免疫细胞化学检测P物质的免疫反应性，用银增强金法检测受体的免疫反应性。含P物质的终扣与对该受体呈阳性和阴性标记的树突形成突触。P物质终扣与神经激肽-1免疫反应性树突形成的突触处通常不存在受体免疫反应性。得出的结论是，P物质可能通过间接的非突触机制调节交感神经节前神经元的大部分活动。
