下丘脑室旁核神经元多重神经支配的电镜研究

DIRECT PATHWAY BETWEEN INSULAR CORTEX AND DORSAL MOTOR NUCLEUS OF THE VAGUS NERVE IN RAT:ALGHT AND ELECTRON MICROSCOPIC STUDY

为了探讨下丘脑神经内分泌的突触调控机制，本文用电镜细胞化学与免疫电镜双标技术相结合的方法，研究了大鼠下丘脑室旁核神经元的多重神经支配。即先用６－ＯＨＤＡ损毁ＣＡ能神经末梢，再于振动切片上用包埋前免疫电镜法，分别以ＤＡＢ和ＴＡＢ为呈色剂先后对肽能（ＯＴ或ＳＰ）神经元和ＧＡＢＡ神经元进行双重标记。电镜观察结果表明：在下丘脑室旁核内存在肽能（ＯＴ、ＳＰ）和氨基酸（ＧＡＢＡ）能神经元及ＣＡ神经末梢；ＯＴ神经元通过轴一树突触接受ＧＡＢＡ和ＣＡ神经支配；ＳＰ神经元通过轴－树突触接受ＣＡ和ＳＰ神经支配；ＧＡＢＡ神经元则可通过轴－树突触接受ＯＴ、ＳＰ、ＣＡ和ＧＡＢＡ等神经支配。本研究首次得到了下丘脑神经元接受多重神经支配的超微结构证据，其意义在于为同时研究下丘脑神经内分泌活动的多种突触调控提供形态学依据。

HRP-labeled terminals and 3H-leucine were distributed densely in the bilateral,but more densely contralateral nucleus of tractus solitarius(NST)and the periphery of the dorsal motor nucleus of the vagus nerve(DMV)following injection of WGA-HRP and3H-leucine into the insular cortex in the rat,respectively.The labeled terminals were also found in the DMV,When the bilateral insular cortex were destroyed and CB-HRP was injected into the wall of the rat stomach,degenerating terminals in the cross region between the NST and DMV were electron dense with electron microscope,The degenerating axon terminals made synaptic contacts with HRP-labeled cell bodies and dendrites.All these results indicate that a direct pathway exists between the insular cortex and the dorsal motor neurons of the vagus nerve innervating stomach in the DMV.