大鼠蓝斑核内神经激肽1受体阳性神经元与Y-氨基丁酸和P物质样阳性终末的联系

Connections between the neurokinin 1 receptor-like immunoreactive neurons and the T-aminobutyric acidor substance P-positive axonal terminals in locus coeruleus of the rat

目的观察大鼠蓝斑核内神经激肽1（NK1）受体阳性神经元与Y-氨基丁酸（GABA）、P物质（sP）样阳性终末之间的关系。方法选用250～300g雄性SD大鼠40只，分别采用免疫荧光双重组织化学染色结合免疫前包埋电镜双重染色方法，观察GABA、SP样阳性终朱与大鼠蓝斑核内NKI受体阳性神经元的联系。结果激光共聚焦显微镜下可见GABA、SP样阳性终末与NK1受体阳性神经元之间形成密切接触。在电镜下可见二氨基联苯胺（DAB）反应产物标记的GABA阳性纤维和终末与免疫金颗粒标记的NK1受体阳性神经元胞体及其树突之间形成以对称性为主的突触联系；DAB反应产物标记的SP阳性纤维和终末与免疫金颗粒标记的NK1受体阳性神经元胞体及其树突之间形成以非对称性为主的突触联系。结论蓝斑核内GABA和sP能终末与NK1受体阳性神经元形成密切接触，提示蓝斑核内的NK1受体阳性神经元可能接受GABA或SP样阳性终末的调控。

Objective To investigate the connections between neurokinin 1 （NK1） receptor-like immunoreactive （LI） neurons and -aminobutyric acid- （GABA）, substance P- （SP） positive axonal terminals in Locus Coeruleus （LC） of the rat. Methods Immunofluorecent histochemical double-staining combining double-staining of electron microscope technique was used to observe the connections between NKI receptor-LI neurons and GABA- or SP-positive axonal terminals in 10 male SD rats （250 -300 g）. Results Under laser confocal microscopy, some of these GABA-, SP-LI axon terminals were observed to make close appositions with NKI receptor-LI neuronal cell bodies and dendritic processes. Under electron microscope, some of these GABA-LI axon terminals by diaminobenzidine（DAB） were observed principally to make symmetric synapses with NK1 receptor-LI neuronal cell bodies and dendritic processes labeled with nano-gold particles. Some of these SP-LI axon terminals labeled by DAB were observed principally to make asymmetric synapses with NK1 receptor-LI neuronal cell bodies and dendritic processes labeled with nanogold particles. Conclusions GABA-, SP-LI axon terminals were observed to make close appositions with NKI receptor-LI neuronal cell bodies and dendritic processes within LC. The NK1 receptor-LI neurons within LC are regulated by the GABA or SP-positive axonal terminals.