{"title":"Modulatory effects of oligodendrocytes on the conduction velocity of action potentials along axons in the alveus of the rat hippocampal CA1 region.","authors":"Yoshihiko Yamazaki, Yasukazu Hozumi, Kenya Kaneko, Toshimichi Sugihara, Satoshi Fujii, Kaoru Goto, Hiroshi Kato","doi":"10.1017/S1740925X08000070","DOIUrl":null,"url":null,"abstract":"<p><p>Like neurons and astrocytes, oligodendrocytes have a variety of neurotransmitter receptors and ion channels. However, except for facilitating the rapid conduction of action potentials by forming myelin and buffering extracellular K(+), little is known about the direct involvement of oligodendrocytes in neuronal activities. To investigate their physiological roles, we focused on oligodendrocytes in the alveus of the rat hippocampal CA1 region. These cells were found to respond to exogenously applied glutamate by depolarization through N-methyl-D-aspartate (NMDA) receptors and non-NMDA receptors. Electrical stimulation of the border between the alveus and stratum oriens evoked inward currents through several routes involving glutamate receptors and inward rectifier K(+) channels. Moreover, electrical stimulation resembling in vivo activity evoked long-lasting depolarization. To examine the modulatory effects of oligodendrocytes on neuronal activities, we performed dual, whole-cell recording on CA1 pyramidal neurons and oligodendrocytes. Direct depolarization of oligodendrocytes shortened the latencies of action potentials evoked by antidromic stimulation. These results indicate that oligodendrocytes increase the conduction velocity of action potentials by a mechanism additional to saltatory conduction, and that they have active roles in information processing in the brain.</p>","PeriodicalId":19153,"journal":{"name":"Neuron glia biology","volume":"3 4","pages":"325-34"},"PeriodicalIF":0.0000,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1740925X08000070","citationCount":"84","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Neuron glia biology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1017/S1740925X08000070","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 84
Abstract
Like neurons and astrocytes, oligodendrocytes have a variety of neurotransmitter receptors and ion channels. However, except for facilitating the rapid conduction of action potentials by forming myelin and buffering extracellular K(+), little is known about the direct involvement of oligodendrocytes in neuronal activities. To investigate their physiological roles, we focused on oligodendrocytes in the alveus of the rat hippocampal CA1 region. These cells were found to respond to exogenously applied glutamate by depolarization through N-methyl-D-aspartate (NMDA) receptors and non-NMDA receptors. Electrical stimulation of the border between the alveus and stratum oriens evoked inward currents through several routes involving glutamate receptors and inward rectifier K(+) channels. Moreover, electrical stimulation resembling in vivo activity evoked long-lasting depolarization. To examine the modulatory effects of oligodendrocytes on neuronal activities, we performed dual, whole-cell recording on CA1 pyramidal neurons and oligodendrocytes. Direct depolarization of oligodendrocytes shortened the latencies of action potentials evoked by antidromic stimulation. These results indicate that oligodendrocytes increase the conduction velocity of action potentials by a mechanism additional to saltatory conduction, and that they have active roles in information processing in the brain.
与神经元和星形胶质细胞一样,少突胶质细胞具有多种神经递质受体和离子通道。然而,除了通过形成髓磷脂和缓冲细胞外K(+)来促进动作电位的快速传导外,人们对少突胶质细胞直接参与神经元活动知之甚少。为了研究它们的生理作用,我们重点研究了大鼠海马CA1区肺泡中的少突胶质细胞。这些细胞通过n-甲基- d -天冬氨酸(NMDA)受体和非NMDA受体去极化,对外源性谷氨酸产生反应。通过谷氨酸受体和向内整流K(+)通道,电刺激肺泡和取向层之间的边界引起向内电流。此外,类似于体内活动的电刺激引起了持久的去极化。为了研究少突胶质细胞对神经元活动的调节作用,我们对CA1锥体神经元和少突胶质细胞进行了双全细胞记录。少突胶质细胞直接去极化可缩短反激刺激引起的动作电位潜伏期。这些结果表明,少突胶质细胞增加动作电位的传导速度的机制除了跳跃式传导之外,它们在大脑的信息处理中起着积极的作用。