主动睡眠无张力状态下腰段运动神经元的突触后抑制性控制：士的宁对运动神经元特性的影响。
The postsynaptic inhibitory control of lumbar motoneurons during the atonia of active sleep: effect of strychnine on motoneuron properties.
作者信息
Soja P J, López-Rodríguez F, Morales F R, Chase M H
机构信息
Department of Physiology, UCLA School of Medicine 90024.
出版信息
J Neurosci. 1991 Sep;11(9):2804-11. doi: 10.1523/JNEUROSCI.11-09-02804.1991.
The present study examined the effects of strychnine on the tonic hyperpolarization and the changes in membrane properties of lumbar motoneurons that occur during active sleep. To carry out these studies, intracellular recordings from lumbar motoneurons were combined with the juxtacellular microiontophoretic application of strychnine in chronic, undrugged, normally respiring cats. During active sleep, compared to quiet sleep, motoneurons that were not exposed to strychnine exhibited tonic hyperpolarization, a decrease in cell excitability, and an increase in membrane conductance; they were also bombarded by high-frequency, large-amplitude IPSPs. In conjunction with the juxtacellular application of strychnine, there was a marked reduction in the degree of hyperpolarization during active sleep; motoneuron excitability was no longer suppressed, and there was a reduction in the increase in membrane conductance. In addition, the large-amplitude IPSPs were blocked. These results identify glycine as the neurotransmitter responsible for the state-dependent changes in membrane properties and the hyperpolarization of motoneurons that takes place during active sleep.
本研究考察了士的宁对主动睡眠期间腰段运动神经元的紧张性超极化及膜特性变化的影响。为开展这些研究，在慢性、未用药、正常呼吸的猫身上，将腰段运动神经元的细胞内记录与士的宁的旁细胞微量离子电泳应用相结合。在主动睡眠期间，与安静睡眠相比，未接触士的宁的运动神经元表现出紧张性超极化、细胞兴奋性降低以及膜电导增加；它们还受到高频、大幅度抑制性突触后电位（IPSPs）的轰击。在旁细胞应用士的宁的同时，主动睡眠期间超极化程度显著降低；运动神经元兴奋性不再受到抑制，膜电导增加也有所减少。此外，大幅度IPSPs被阻断。这些结果表明，甘氨酸是负责主动睡眠期间膜特性的状态依赖性变化以及运动神经元超极化的神经递质。
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