Short-term plasticity of descending synaptic input to phrenic motoneurons in rats
Short-term plasticity of descending synaptic input to phrenic motoneurons in rats
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DOI：
10.1152/japplphysiol.00599.2002
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发表时间：
2003-04-01
影响因子：
3.3
通讯作者：
McCrimmon, DR
中科院分区：
文献类型：
--
作者：
Hayashi, F;Hinrichsen, CFL;McCrimmon, DR
呼吸传入刺激可引起呼吸运动输出增加，持续时间超过刺激时间数秒至数分钟[短时程增强（STP）]。本研究在麻醉、切断迷走神经、瘫痪的大鼠中检查脊髓机制对STP的潜在贡献。在C-1脊髓横断后，C-1-C-2侧索的刺激串（100 Hz，5-60 s）引起膈神经活动的STP，刺激后数秒达到峰值。细胞内记录显示，单个膈运动神经元表现出三种不同的反应之一：1）去极化，达到峰值数秒后刺激，2）去极化刺激期间，然后指数复极化刺激后，和3）运动神经元去极化到一个新的，相对稳定的水平，刺激终止后保持的行为。在STP期间，单刺激脉冲引起的兴奋性突触后电位更大，更长。总之，重复激活膈运动神经元的下行输入导致膈运动神经元的短暂去极化，兴奋性突触后电位的增强，与STP的贡献一致。
Respiratory afferent stimulation can elicit increases in respiratory motor output that outlast the period of stimulation by seconds to minutes [short-term potentiation (STP)]. This study examined the potential contribution of spinal mechanisms to STP in anesthetized, vagotomized, paralyzed rats. After C-1 spinal cord transection, stimulus trains (100 Hz, 5-60 s) of the C-1-C-2 lateral funiculus elicited STP of phrenic nerve activity that peaked several seconds poststimulation. Intracellular recording revealed that individual phrenic motoneurons exhibited one of three different responses to stimulation: 1) depolarization that peaked several seconds poststimulation, 2) depolarization during stimulation and then exponential repolarization after stimulation, and 3) bistable behavior in which motoneurons depolarized to a new, relatively stable level that was maintained after stimulus termination. During the STP, excitatory postsynaptic potentials elicited by single-stimulus pulses were larger and longer. In conclusion, repetitive activation of the descending inputs to phrenic motoneurons causes a short-lasting depolarization of phrenic motoneurons, and augmentation of excitatory postsynaptic potentials, consistent with a contribution to STP.