PATCH CLAMP ANALYSES ON DEVELOPMENTAL CHANGES IN GABA RECEPTOR FUNCTION

膜片钳分析 GABA 受体功能的发育变化

• 批准号: 05454681
• 负责人: TAKAHASHI Tomoyuki
• 金额: $ 4.22万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05454681/
• 关键词: GABA; IPSC; Receptor; Synapse; Patch Clamp; Ontogeny; Spinal Cord; Thalamus; 生後発達; スライス; 単一チャネル電流

We made whole cell recordings of GABAergic IPSCs from spinal, visual cortical and thalamic neurons of rats at the postnatal period ranging from 0 day to 21 days. We also made outside-out patch recordings of GABA-gated Cl channel currents from patches excised from spinal neurons. The GABA-gated channels were characterized with flickerings within a burst. Ensemble averaging of the bursts aligned at the onset gave currents having similar time course with the GABAergic IPSCs, suggesting that the burst duration might determine the decay time course of GABAergic IPSCs. In the spinal cord, no significant difference was observed for the decay time courses of the IPSCs between one-day old and 16 day old animals. This was also the case for the IPSCs recorded from visual cortical neurons. It has been reported recently that GABA receptor subunit switches from immature subtype alpha2 to mature alpha1 subunit within 2-3 weeks after birth prominently in rat thalamic neurons. However, we could not find a marked difference in the time course of IPSCs between neonatal and 3 week old animals. These results were somewhat unexpected because a clear developmental shortening in the time course of synaptic currents has been observed for glycinergic IPSCs and also for cholinergic end-plate currents, in both cases subunits being switched from immatre to mature forms. It is concluded that subunit switching of GABA receptor alphasubunit may not produce a significant changes in the time course of inhibitory synaptic responses.

我们对出生后0 - 21天的大鼠脊髓、视皮层和丘脑神经元的GABA能IPSC进行了全细胞记录。我们还从脊髓神经元上切下的贴片记录了GABA门控的Cl通道电流。GABA门控通道的特征在于在爆发内的闪烁。在发作时对齐的爆发的包围平均给出与GABA能IPSC具有类似时间过程的电流，这表明爆发持续时间可能决定GABA能IPSC的衰减时间过程。在脊髓中，未观察到1日龄和16日龄动物之间IPSC的衰减时间过程的显著差异。这也是从视觉皮层神经元记录的IPSC的情况。近年来有研究表明，大鼠丘脑神经元GABA受体亚单位在出生后2-3周内发生了显著的转变，即由未成熟的α 2亚单位转变为成熟的α 1亚单位。然而，我们没有发现新生和3周龄动物之间IPSC的时间过程有显著差异。这些结果有些出乎意料，因为已经观察到甘氨酸能IPSC和胆碱能终板电流的突触电流时程的明显发育缩短，在这两种情况下，亚基从未成熟转变为成熟形式。结果表明，GABA受体亚基转换可能不影响抑制性突触反应的时程。

项目成果

Hayashi,Y.: "Role of a metabotropic glutamate receptor in synaptic modulation in the accessory olfactory bulb." Nature. 366. 687-690 (1993)

Hayashi,Y.：“代谢型谷氨酸受体在副嗅球突触调节中的作用。”

Takahashi,T.: "Different types of calcium channels mediate central synaptic transmission." Nature. 366. 156-158 (1993)

Takahashi,T.：“不同类型的钙通道介导中枢突触传递。”

Kobayashi,S: "Whole-cell properties of temperature-sensitive neurons in rat hypothalamic slices." Proc.R.Soc.Lond B.251. 89-94 (1993)

Kobayashi，S：“大鼠下丘脑切片中温度敏感神经元的全细胞特性。”

Momiyama,A.: "Calcium channels responsible for potassium-induced transmitter release at rat cerebellar synapses." Journal of Physiology(London). 476.2. 197-202 (1994)

Momiyama，A.：“钙通道负责大鼠小脑突触钾诱导的递质释放。”

Hayashi, Y., Momiyama, A., Takahashi, T., Ohishi, H., Ogawa-Meguro, R., Shigemoto, R., Mizuno, N.& Nakanishi, S.: "Role of a metabotropic glutamate receptor in synaptic modulation in the accessory olfactory bulb." Nature. 366. 687-690 (1993)

Hayashi, Y.、Momiyama, A.、Takahashi, T.、Ohishi, H.、Okawa-Meguro, R.、Shigemoto, R.、Mizuno, N.