Prime L, Pichon Y, Moore L E
Laboratoire de Neurobiologie des Réseaux Sensorimoteurs, Unité Propre de Recherche de l'Enseignement Supérieur Associée 7060 au Centre National de la Recherche Scientifique, Université de Paris V, VII, 75270 Paris Cedex, France.
J Neurophysiol. 1999 Aug;82(2):1069-73. doi: 10.1152/jn.1999.82.2.1069.
The patch-clamp technique was used to measure the effect of N-methyl-D-aspartate (NMDA) on Xenopus embryonic neurons in an isolated, but intact spinal cord. Whole cell recordings were done at external calcium concentrations of 1 mM. NMDA alone (50-200 microM) or in association with 10 microM serotonin or glycine induced oscillatory activity in most presumed motoneurons, which were therefore considered part of rhythm generating networks. In the presence of TTX, one-half of these neurons maintained this activity. The oscillations fell into two main categories: voltage-dependent, low-frequency (0.3-0.5 Hz) and voltage-independent, high-frequency (3-8 Hz) oscillations. NMDA alone induced TTX-insensitive oscillations in one-third of the neurons; however, the percentage of neurons showing oscillations was greater in the presence of exogenous 5-hydroxytryptamine (5-HT) or glycine. Because these observations were made at embryonic stages where little or no serotonergic innervation exists, it is likely that NMDA-induced intrinsic oscillatory activity in Xenopus embryonic neurons does not require 5-HT.
膜片钳技术用于测量N-甲基-D-天冬氨酸（NMDA）对分离但完整的脊髓中非洲爪蟾胚胎神经元的影响。在外部钙浓度为1 mM的条件下进行全细胞记录。单独使用NMDA（50 - 200微摩尔）或与10微摩尔血清素或甘氨酸联合使用时，在大多数假定的运动神经元中诱导出振荡活动，因此这些神经元被认为是节律产生网络的一部分。在存在河豚毒素（TTX）的情况下，这些神经元中有一半保持这种活动。振荡分为两大类：电压依赖性低频（0.3 - 0.5赫兹）振荡和电压非依赖性高频（3 - 8赫兹）振荡。单独使用NMDA在三分之一的神经元中诱导出对TTX不敏感的振荡；然而，在外源5-羟色胺（5-HT）或甘氨酸存在的情况下，显示振荡的神经元百分比更高。由于这些观察是在几乎没有或不存在血清素能神经支配的胚胎阶段进行的，因此非洲爪蟾胚胎神经元中NMDA诱导的内在振荡活动可能不需要5-HT。
