Impulses and pressure waves cause excitement and conduction in the nervous system
Impulses and pressure waves cause excitement and conduction in the nervous system
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DOI：
10.1016/j.mehy.2013.07.049
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发表时间：
2013-11-01
影响因子：
4.7
通讯作者：
Barz, Ulrich
中科院分区：
文献类型：
--
作者：
Barz, Helmut;Schreiber, Almut;Barz, Ulrich
一般认为，神经的兴奋和传导是由电压变化引起的。然而，液体流入弹性管会释放脉冲或压力波。因此，离子电流的流入，分别进入弹性神经元细胞和纤维的流体运动也诱导冲动。电荷载体的这种运动通过电压设备测量为振荡或动作电位，但电压变化可能是（机械）脉冲的附带现象。脉冲波可以具有很高的速度。管壁越硬或越无弹性，脉冲的速度就越大。髓鞘引起神经纤维壁的显著硬化，并且有髓鞘纤维具有高达120 m/s的传导速度。Ranvier淋巴结的液体流入周期性地增强神经纤维中的冲动波，作者认为肌肉终板也是轴突冲动向肌纤维内部传导的导体，而乙酰胆碱的胞吐进入突触间隙可能是轴突冲动的放大器。细胞内肌动蛋白丝也可能影响神经元膜的运动。许多感觉神经细胞由于外源性或内源性的机械脉冲而兴奋。这可能是合理的，这种冲动直接传导到背根神经节中的感觉神经细胞体，而不需要电能的转换。激发传导发生时没有显著的能量消耗，因为离子电流通过膜的流动相当于浓度梯度。脉冲波引起细胞和纤维壁的脂质膜的短延伸，因此它们可以诱导所包含的离子通道的打开和关闭。这种机制同样作用于“电压门控”和“配体门控”通道。神经冲动的概念有助于理解神经生理学的其他观点或神经疾病。这包括例如，阿尔茨海默氏痴呆症的脑震荡和病理组织学发现。为了验证神经系统中（机械）脉冲的概念，有必要在非常小的维度上进行生物物理或机械研究，作者希望为此提供足够的刺激。(C)2013作者由爱思唯尔有限公司出版。保留所有权利。
It is general accepted, that nerval excitement and conduction is caused by voltage changes.However, the influx of fluid into an elastical tube releases impulses or pressure waves. Therefore an influx of ion currents, respectively fluid motions into the elastic neuronal cells and fibres also induce impulses. This motion of charge carriers are measured by voltage devices as oscillations or action potentials, but the voltage changes may be an epiphenomenon of the (mechanical) impulses.Impulse waves can have a high speed. As stiffer or inelastic a tube wall, the greater is the speed of the impulse. Myelin sheaths cause a significant stiffening of the nerve fibre wall and myelinated fibres have a conduction velocity up to 120 m/s. The influx of fluid at the nodes of Ranvier intensifies periodically the impulse wave in the nerve fibres.The authors suggest that also the muscle end-plate acts as a conductor of axonal impulses to the inner of the muscle fibres and that the exocytosis of acetylcholine into the synaptic cleft may be an amplifier of the axonal impulse. It is discussed that intracellular actin filaments may also influence motions at the neuronal membrane.Many sensory nerve cells are excited due to exogenous or endogenous mechanical impulses. It may plausible that such impulses are conducted directly to the sensory nerve cell bodies in the dorsal root ganglia without the transformation in electric energy. Excitation conduction happens without noteworthy energy consumption because the flow of ion currents through the membranes takes place equivalent to the concentration gradient.Impulse waves cause short extensions of the lipid membranes of the cell- and fibres walls and therefore they can induce opening and closing of the included ion channels. This mechanism acts to "voltage gated" and "ligand-gated" channels likewise.The concept of neuronal impulses can be helpful to the understanding of other points of neurophysiology or neuronal diseases. This includes e.g., the brain concussion and pathohistological findings in Alzheimer dementia.To verify the concept of (mechanical) impulses in the nervous system it is necessary to carry out biophysical or mechanical investigations in very small dimensions and the authors hope to give for this a sufficient stimulus. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.