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Static and dynamic analyses of reverberating neuronal within the brainstem.

脑干内反射神经元的静态和动态分析。

基本信息

批准号：
62480104
负责人：
MORI Shigemi
金额：
$ 3.9万
依托单位：
Asahikawa Medical College
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

In this study, we have tried to elucidate the presence of reverberating neuronal circuits within the brainstem and the function of them on the control of postural muscle tone in the cats. Our immunohistochemical studies by using a PHA-L technique have demonstrated that there are neuronal connections between the left and the right nucleus reticularis pontis oralis (NRPo), and the NRPo and bilateral nucleus reticularis gigantocellularis (NRGc). Descending axons from the NRGc coursed bilaterally through the ventral and ventrolateral funiculi of the cervical cord. Single axon collaterals arising from the descending axons terminated mainly in the Rexed's laminae VII and VIII, where interneurons are located. Microinjections of carbachol into the unilateral NRPo resulted in tonic activation of a group of cells in the NRPo and in the NRGc. Cells in the NRGc were considered to be activated synaptically by the increased neuronal activity descending from the NRPo. Descending axons of these NRGc cells reached as far caudal as the lumbosacral cord. These NRGc cells were found to exert non-reciprocal postsynaptic inhibitory effects upon hindlimb alpha-motoneurons innervating extensor and flexor muscles. All these results suggested that there are reverberating neuronal circuits within the brainstem, and the NRGc cells are the output cells of the brainstem relaying suprabulbar sustained neuronal activity to the spinal cord. Tonic activation of these NRGc cells results in tonic inhibition of alpha-motoneurons, and consequently tonic suppression of postural muscle tone.

在这项研究中，我们试图阐明脑干内的混响神经元回路的存在，以及它们对姿势肌张力控制的功能。我们用PHA-L免疫组化技术研究表明，有神经元之间的联系，在左侧和右侧的脑桥口网状核（NRPo），和NRPo和双边的网状核神经细胞（NRGc）。下行轴突从NRGc coursed双侧通过腹侧和腹外侧索的颈髓。从下行轴突产生的单轴突侧支主要终止于Rexed的第七层和第八层，中间神经元位于其中。将卡巴胆碱微量注射到单侧NRPo中导致NRPo和NRGc中的一组细胞的紧张性激活。NRGc中的细胞被认为是通过从NRPo下降的增加的神经元活性而被突触激活。这些NRGc细胞的下行轴突到达远尾侧的腰骶髓。发现这些NRGc细胞对支配伸肌和屈肌的后肢α-运动神经元施加非互惠的突触后抑制作用。这些结果表明，脑干内存在反射性神经回路，NRGc细胞是脑干的输出细胞，将球上持续的神经元活动传递给脊髓。这些NRGc细胞的紧张性激活导致α运动神经元的紧张性抑制，并因此导致姿势肌张力的紧张性抑制。