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Dissociation between activation of higher nervous system and postural muscle tone in cats.

猫高级神经系统的激活与姿势肌张力之间的分离。

基本信息

批准号：
60480112
负责人：
MORI Shigemi
金额：
$ 3.97万
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：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

项目摘要

A ponto-medullary and spinal system, that is involved in postural suppression, has been identified by means of axonal flow techniques for both retro- and antero-grade tracing. It originated from cells in the nucleus reticularis pontis oralis (Po0) and the descending axons coursed through the dorsal portion of the caudal tegmental field (DTF) in the pons along its midline. They terminated on somata of cells in the nucleus reticularis gigantocellularis (Gc), and these cells projected their descending axons to the lumbar spinal cord. The cells in the nucleus Gc also projected their ascending axons to the nucleus Po0 suggesting an existence of "reverberating neuronal circuits" between the nucleus Po0 and the nucleus Gc. A single stimulation delivered to the DTF area activated antidromically cells in the nucleus Po0. Cells in the nucleus Gc were activated orthodromically by the same stimulation and were activated antidromically by stimulating the spinal cord. In reflexively standing decerebrate cats, focal injection of carbachol (long-acting cholinomimetic agent resistant to acethylcholinesterases) into the nucleus Po0 resulted in the suppression of extensor muscle tone in the hindlimbs. With this injection, cells both in the nucleus Po0 and the nucleus Gc started to fire tonically, and the membrane potential of alpha-motoneurons (MNs) innervating extensor muscles were hyperpolarized. The effects exerted upon alpha-MNs were quite similar to those induced upon them by a train pulse stimulation delivered to the DTF area. Averaging of intracellularly recorded membrane potentials of alpha-MNs, triggered by the extracellularly recorded action potentials of the cells in the nucleus Gc, revealed postsynaptic inhibitory potentials both in extensor and flexor alpha-MNs innervating hindlimbs. All these results clearly demonstrated that cells in the nucleus Po0 and those in the nucleus Gc play the roles of "trigger neurons" and "relay neuron", respectively, in postural suppression.

一个桥-髓系和脊柱系统，参与姿势抑制，已确定通过轴突流技术的复古和前级追踪。它起源于口桥网状核（Po0）的细胞，下行轴突沿其中线穿过桥脑尾侧被区（DTF）的背侧部分。它们终止于巨细胞网状核（Gc）的细胞体，这些细胞将其下行轴突投射到腰椎。Gc核内的细胞也将其上行轴突投射到Po0核，表明Po0核和Gc核之间存在“混响神经元回路”。对DTF区域的单一刺激激活了Po0核中的逆转录细胞。Gc核的细胞在同样的刺激下呈正向激活，而在脊髓刺激下呈反向激活。在条件反射站立的脱脑猫中，向Po0核局灶性注射恰巴醇（抗乙酰胆碱酯酶的长效拟胆碱剂）可抑制后肢伸肌张力。注射后，Po0核和Gc核细胞均开始强直放电，支配伸肌的-运动神经元（MNs）膜电位呈超极化。施加在α - mns上的影响与传递到DTF区域的列脉冲刺激对它们产生的影响非常相似。由Gc核细胞外记录的动作电位触发的细胞内记录的α - mns膜电位的平均显示了支配后肢的伸肌和屈肌α - mns的突触后抑制电位。这些结果清楚地表明，Po0核细胞和Gc核细胞在姿势抑制中分别起着“触发神经元”和“中继神经元”的作用。