大鼠运动皮层的胼胝体起源细胞与GABA能终末的突触联系  

CALLOSAL NEURON AND ITS SYNAPTIC CONNECTIONS WITH GABA IMMUNOREACTIVE TERMINALS IN RAT MOTOR CORTEX

作　　者：郑芳[1] 郑则慧[1] 

机构地区：[1]中国科学院上海脑研究所

出　　处：《解剖学报》1997年第4期359-363,I005,共6页Acta Anatomica Sinica

摘　　要：用ＨＲＰ逆行标记结合ＧＡＢＡ免疫组织化学染色法，在电镜下观察大鼠运动皮层胼胝体起源细胞的超微结构特征及其与ＧＡＢＡ能终末的关系。结果表明：大鼠运动皮层内的轴突终末与胼胝体起源细胞胞体仅形成对称型突触，与近端树突梗也形成少量的对称型突触，而与其树突棘则形成非对称型突触。与胞体和近端树突形成对称型突触的轴突终末主要是ＧＡＢＡ能终末。由这些ＧＡＢＡ能终末形成的轴－体突触数量占胞体表面总对称性突触数的８５．６４％（Ⅱ～Ⅲ层）和８２．１１％（Ⅴ～Ⅳ层）；近端树突上ＧＡＢＡ能终末所形成的突触占其表面总对称型突触数的７８．１３％（Ⅱ～Ⅲ层）和８４．７９％（Ⅴ～Ⅵ层）。这一结果提示，联系大鼠两侧运动皮层胼胝体起源细胞的抑制性传入，主要由ＧＡＢＡ能递质来调控。he connections of callosal neurons between primary motor cortex of the two hemispheres establish a important bridge in excitation and inhibition of motor integration , while their GABAergic inhibitory inputs are not clear yet. Using the method of HRP retrograde labeling technique combined with GABA immunohistochemistry, the ultrastructural characteristics of callosal neuron and its synaptic connections with GABAergic terminals in rat motor cortex were investigated. The observation of callosal neurons on ultrathin sections showed that callosal neurons received symmetric synapses on their soma, the proximal dendritic shaft also received several symmetric synapses, and the spine of callosal neurons received asymmetric synapse. Quantitative studies showed that (1) among the symmetric synapses on soma of callosal neurons, of which 8654% were formed by GABA terminals in layers Ⅱ～Ⅲ, 4.84 GABA symmetric synapses/per somatic section, and 82.11% in layers Ⅴ～Ⅵ, 5.17 GABA synapses/per somatic section; (2) most of the synapses on the proximal dendritic shafts of callosal neuron were also GABAergic synapses: for layers Ⅱ～Ⅲ, the percentage of GABAergic symmetric synapses to total symmetric synapses was 78.13%, 3.04 GABAergic synapses/per 10 μm dendrite length, and for layers Ⅴ～Ⅵ, 84.79%,3.01 GABAergic synapses/per 10μm dendrite length. These results suggest that the callosal neurons, which is functionally associated with coordination of bilateral motor cortex, are principally mediated by GABAergic neurotransmitter in their inhibitory inputs.

关 键 词：胼胝体 神经元 GABA能终末 运动皮层 大鼠 

分 类 号：R338.13[医药卫生—人体生理学] R329.48[医药卫生—基础医学]