大鼠5-HT阳性终末与三叉神经运动神经元的突触联系

Synaptic connections between 5-HT immunoreactive terminals and motoneurons in rat trigeminal motor nucleus

目的 定量分析大鼠 5 -羟色胺 (5 - HT)阳性终末与三叉神经运动核内胆碱乙酰转移酶 (Ch AT)阳性运动神经元之间突触联系的超微结构特点 .方法 雄性成年 SD大鼠 2 0只 ,经升主动脉灌注固定 .用振动切片机横切脑干 ,片厚 5 0μm.将切片用免疫组织化学双标染色 ,染色结果在电镜下观察 .结果 三叉神经运动神经元均呈 Ch AT阳性 ;5 - HT阳性终末主要含透明圆形小泡 (直径 2 0～ 30 nm) ,透明扁平形小泡 (长径 2 5～ 35 nm)和大颗粒囊泡 (直径≥ 5 0 nm)较少见 . 5 -HT阳性终末与 Ch AT阳性运动神经元之间主要形成非对称型突触联系 ,对称型突触较少见 .非对称型突触的突触间隙明显宽于对称型突触的突触间隙 .结论 5 - HT阳性终末主要含透明圆形小泡 ,它们与 Ch

AIM Quantitative analyses on the ultrastructural properties of the synaptic connections between serotonin (5 HT) immunopositive terminals and choline acetyltransferase (ChAT) immunoreactive motor neurons in the rat trigeminal motor nucleus. METHODS Twenty male adult rats were perfused through the ascending aorta. The brainstem was transversely cut into 50 μm thick sections by a microslicer. The sections were immunohistochemically double stained. The staining results were observed under electron microscope. RESULTS All trigeminal motor neurons showed ChAT immunoreactivities. In the trigeminal motor nucleus, 5 HT immunoreactive axon terminals were mainly filled with transparent round synaptic vesicles (diameter 20~30 nm), while the number of the transparent flattened vesicles (diameter 25~35 nm) and large granular synaptic vesicles (diameter≥50 nm) were small. Asymmetrical synapses were predominated between the synaptic connections of 5 HT immunoreactive axon terminals and ChAT immunoreactive motor neurons in the rat trigeminal motor nucleus, and the number of symmetrical synapses were small. The synaptic cleft in the asymmetrical synapse was wider than that in the symmetrical synapse. CONCLUSION 5 HT immunoreactive axon terminals are mainly filled with transparent round synaptic vesicles. 5 HT immunoreactive axon terminals principally make asymmetrical synapse with ChAT immunoreactive motor neurons in the rat trigeminal motor nucleus.