Motor unit and neuromuscular junction remodeling with aging.
Motor unit and neuromuscular junction remodeling with aging.
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运动单位和神经肌肉接头随着衰老而重塑。
DOI：
10.2174/1874609811104030209
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发表时间：
2011
影响因子：
--
通讯作者：
M. Deschenes
中科院分区：
文献类型：
--
作者：
M. Deschenes
神经肌肉系统是人体最大、最重要的器官系统之一。神经肌肉系统的功能和质量在自然衰老过程中逐渐退化。神经肌肉系统由单独的运动单位组成，每个运动单位都有一个运动神经元和它所支配的所有肌肉纤维。运动单位也表现出与年龄相关的重塑，如数量减少，肌肉纤维萎缩，但每个运动单位的纤维数量增加。运动神经元和它们所支配的肌肉纤维之间的通信是一种特殊的突触，被称为神经肌肉接头。衰老也会引起突触的重塑，将运动神经末梢与肌肉纤维表面的一小块(0.1%)称为终板的区域连接起来。衰老的神经肌肉接头表现为突触前神经末梢分支和突触后神经递质受体位置分布的升高。这种解剖重建伴随着与年龄相关的神经生理变化，包括量子含量的增加，在连续刺激突触前神经元的过程中，终板潜在强度会更快地下降。此外，越来越多的证据表明，衰老影响了NMJ适应增加和减少体力活动的能力。由于工业化国家被认为是老龄化的人数显著增加，我们有必要扩大我们对衰老对神经肌肉系统、其组成运动单位以及允许神经细胞和肌肉纤维有效合作的神经肌肉连接的影响的理解。
The neuromuscular system is one of the largest and most vital organ systems of the body. The function and mass of the neuromuscular system gradually deteriorate during the natural process of aging. The neuromuscular system is comprised of individual motor units, each of which features a single motor neuron and all the muscle fibers it innervates. Motor units also demonstrate age-related remodeling such as reduced number, muscle fiber atrophy, but an increased number of fibers per motor unit. Enabling communication between motor neurons and the muscle fibers they innervate is a specialized synapse known as the neuromuscular junction. Aging, too, elicits remodeling of this synapse joining motor nerve terminal endings with a small ( < 0.1%) area of the muscle fiber's surface called the endplate. Aged neuromuscular junctions exhibit elevations in pre-synaptic nerve terminal branching, and in the post-synaptic distribution of receptor sites for neurotransmitter. This anatomical remodeling is coupled with age-related neurophysiological alterations including increased quantal content, with a more rapid rundown of endplate potential strength during continuous stimulation of the pre-synaptic neuron. Moreover, there is a growing body of evidence indicating that aging impacts the capacity of the NMJ to adapt to increased, as well as decreased physical activity. Because of the marked increase in the number of people considered to be aged in industrialized countries, it is essential to expand our understanding of the influence of aging on the neuromuscular system, its constituent motor units, and the neuromuscular junctions which allow neural cells and muscle fibers to effectively work together.