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Noval mechanism for neural control of muscle in crustacean heart : analysis of graded neuromuscular transmission

甲壳动物心脏肌肉神经控制的新机制：分级神经肌肉传递分析

基本信息

批准号：
11640675
负责人：
YAMAGISHI Hiroshi
金额：
$ 0.45万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640675/
关键词：
synapse neuromuscular transmission heart crustacea フナムシノンスパイク

项目摘要

Signal transmission in neural synaps and neuromuscular junctions is achieved by all-or-none nerve impulses. Recently, however, graded synaptic transmission has been found to play an important role for signal transmission in the central nervous systems. Even in the neuromuscular junction, it has been demonstrated experimentally that, the presynaptic nerve terminal of the motoneuron release transmitter depending on changes in the membrane potential and produce graded junctional potentials in the post synaptic membrane of the muscle. Howener, the motoneuron is generally distant from the target muscle and graded transmission in the neuromuscular junction has not been reported. The heart of many crustaceans is neurogenic and the heartbeat is initiated by the cardiac ganglion. The cardiac ganglion of the isopod Ligia is composed of six neurons with pacemaker and motor functions and these neurons fire synchronously through electrical connections. Periodic bursts of nerve impulses generated in the cardiac ganglion induce action potentials of the cardiac muscle and cause heartbeats. In the heart of Ligia, the cardiac muscle also has pacemaker propertied, while the cardiac ganglion acts as a primary pacemaker entraining the mucle rhythm into the ganglion rhythm through the neuromuscular junctions. In the present study, neuromuscular transmission between the cardiac ganglion and cardiac muscle was further examined. The results showed that the cardiac ganglion control the cardiac mucel through not only impulse-mediated transmission but also graded transmission. This is the first report of functional graded synaptic transmission in the neuromuscle juction. The paper including these results has been published.

神经突触和神经肌肉接头中的信号传递是由全有或全无神经冲动实现的。然而，最近发现，分级突触传递在中枢神经系统的信号传递中发挥着重要作用。即使在神经肌肉交界处，实验也证明，运动神经元的突触前神经末梢依赖于膜电位的变化而释放递质，并在肌肉的突触后膜上产生渐变的交感电位。然而，运动神经元一般距离靶肌肉较远，在神经肌肉接头处的分级传递尚未见报道。许多甲壳类动物的心脏是神经性的，心跳是由心脏神经节启动的。等足目Ligia的心脏神经节由6个具有起搏和运动功能的神经元组成，这些神经元通过电连接同步放电。心脏神经节中产生的周期性神经冲动会诱发心肌的动作电位，并引起心跳。在Ligia的心脏，心肌也具有起搏器特性，而心脏神经节则是主要的起搏器，通过神经肌肉连接将粘液节律引入神经节节律。在本研究中，进一步研究了心脏神经节和心肌之间的神经肌肉传递。结果表明，心脏神经节对心脏粘液的调控不仅通过脉冲传递，而且还通过分级传递。这是首次报道神经肌肉连接中的功能性分级突触传递。包括这些结果的论文已经发表。