N-Methyl-D-aspartate-induced oscillations in whole cell clamped neurons from the isolated spinal cord of Xenopus laevis embryos.
N-Methyl-D-aspartate-induced oscillations in whole cell clamped neurons from the isolated spinal cord of Xenopus laevis embryos.
复制标题
N-甲基-D-天冬氨酸诱导的爪蟾胚胎分离脊髓全细胞钳制神经元振荡。
作者：
L. Prime;Y. Pichon;L. Moore
采用膜片钳技术测定了n -甲基- d -天冬氨酸（NMDA）对爪蟾胚胎脊髓神经元的影响。在外部钙浓度为1mm的情况下进行全细胞记录。NMDA单独（50-200微米）或与10微米的5 -羟色胺或甘氨酸联合在大多数假定的运动神经元中诱导振荡活动，因此被认为是节律产生网络的一部分。在TTX存在的情况下，这些神经元中有一半保持这种活动。振荡主要分为两大类：电压相关的低频（0.3-0.5 Hz）和电压无关的高频（3-8 Hz）振荡。NMDA单独在三分之一的神经元中诱导ttx不敏感振荡；然而，在外源性5-羟色胺（5-HT）或甘氨酸的存在下，显示振荡的神经元百分比更大。由于这些观察是在胚胎阶段进行的，在胚胎阶段很少或没有5-羟色胺能神经支配存在，因此nmda诱导的非洲爪蟾胚胎神经元的内在振荡活动可能不需要5-羟色胺。
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.