中缝大核内P物质神经元及其突触关系——免疫电镜研究

SUBSTANCE P NEURONS AND THEIR SYNAPTIC RELATIONS IN THE NUCLEUS RAPHE MAGNUS——AN IMMUNOELECTRON MICROSCOPIC STUDY

用PAP免疫电镜法,观察大鼠中缝大核(NRM)内P物质样免疫反应(SP-li)阳性胞体、纤维及其突触关系。表明NRM内SP-li神经元为梭形,卵圆和多极细胞,散在分布于NRM。SP-li产物定位于神经元的胞质和线粒体、内质网、囊泡等细胞器的外膜。NRM内SP-li轴突包括无髓纤维和有髓纤维,SP-li树突数量较多。SP-1i树突和胞体均接受大量非标记轴突的突触联系,易见SP-li中心树突接受非标记轴突的汇聚传入。SP-li轴突既与非标记树突形成轴(SP)-树突触,也与SP-li树突形成轴(SP)-树(SP)突触。轴-轴(SP)突触包括清亮囊泡型和颗粒囊泡型两种,部分SP-li轴突终末可作为中心轴突接受多个非标记轴突终扣的突触调节。

Substance P-like immunoreactive (SP-li) cell bodies and processes and their synaptic relations with other neural elements in the nucleus raphe magnus (NRM) of rats were studied by electron microscope. The results showed that SP-li neurons are fusiform, oval and multipolar cells which distribute evenly over the nucleus. Immunostaining was present in the cytoplasmic matrix and membranes of mitochondria, endoplasmic reticulum and vesicles. Both unmyelinated and myelinated SP-li axons are found in the NRM. SP-li dendrites are numerous in the NRM. SP-li dendrites and somata are contacted by a variety of round, flat and granular vesicle-containing terminals. A central SP-li dendrite receivie convergent inputs from unlabelled axonal boutons is frequently seen in the NRM. SP-li terminals are presynaptic to the unlabelled dendrites, also some SP-li terminals are apposed or presynaptic to SP-li dendrites. Axo-axonic (SP-li) synapses were found in the NRM. The unlabelled presynaptic boutons contain clear round vesicles or mixed with granular vesicles. A central SP-li terminalis contacted by several unlabelled terminals is also found in the NRM.