大鼠颈上神经节内P物质和降钙素基因相关肽免疫反应纤维的超微结构

大鼠颈上神经节的尾端和头端切断后，用免疫电镜方法研究节内P物质（SP）、降钙素基因相关肽（CGRP）免疫反应神经纤维的超微结构。尾端切断后，节内SP和CGRP免疫反应纤维数量比正常组明显减少，甚至消失。然而，头端切断后，该二种肽能神经数量则无明显变化。以此推测该节内SP、CGRP免疫反应神经纤维是节外起源。尾端切断后少数小强荧光细胞呈SP或CGRP免疫反应。SP阳性轴突与节后神经元紧密接触，但未见突触连结。SP阳性轴突与SP阴性反应树突构成对称性轴树突触。CGRP阳性轴突与阴性反应的小强荧光细胞构成轴体突触。讨论了大鼠颈上神经节内SP、CGRP免疫反应神经纤维的功能。

The Ultrastructure of Substance P-and Calcitonin Gene-Related Peptide Immunoreactive Nerve Fibres in the Rat Superior Cervical Ganglion

Using immunoelectron microscopy,the ultrastructure of substance P (SP)-and calcitonin gene-related peptide (CGRP) immunoreactive nerve fibres were investigated in the superior cervical ganglion (SCG) of rat after transection of the caudal and cranial end of SCG.The number of SP-and CGRP-immunoreactive nerve fibres were markedly decreased or even virtually disappeared after cutting the caudal end of SCG,but no marked change was noted after cranial end of SCG as compared with controls.It can be deduced that in rat SCG SP-and CGRP-IR fibres are of extraganglionic origin.A few small intensely fluorescent (SIF) cells exhibited immunobehaviour to SP-and CGRP-antisera after cutting the caudal end of SCG.SP-IR axon closely contacted with postganglionic neurons.SP-IR axon formed symmetric axo-dendritic synapse with SP-axon which formed symmetric axo-dendritic synapse with SP-negative dendrite.CGRP-IR axon formed symmetric axo-somatic synapse with SP-axon which formed symmetric axo-dendritic synapse with CGRP-negative SIF cell.The roles of SP-and CGRP-IR nerve fibres in SCG of the rat were discused.