Patch-Clamp Analysis on the Mechanism for Inhibitory Synaptic Transmission in Rat Spinal Motoneurone.

大鼠脊髓运动神经元抑制突触传递机制的膜片钳分析。

• 批准号: 01480124
• 负责人: TAKAHASHI Tomoyuki
• 金额: $ 4.1万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01480124/
• 关键词: motoneurones; slices; IPSCs; patch-clamp; spinal cord; バッチクランプ; 抑制性シナプス電流; 量子仮説; whole-cell記録; 素量解析; 二項分布

Tight-seal whole-cell recordings of Inhibitory Postsynaptic Currents (IPSCs) were made from neonatal rat spinal motoneurones. The IPSCs were evoked by stimulating a single internuncial neurone extracellularly. The latency measured from the stimulus artifact to the onset of IPSCs was stable when stimulated at various frequencies (0.2-50 Hz) with the mean latency of 0.6-0.8 ms at 37 C, suggesting the monosynaptic nature of the IPSCs. When the external Ca^<2+> concentration ([Ca]_o) was reduced, the number of failures of IPSCs increased, and the mean amplitude of IPSCs decreased. The relation between [Ca]_o (0.35-1.4mM) and the mean amplitude of IPSCs was linear with a mean slope of 3.1 on double logarithmic co-ordinates. The amplitude of IPSCs decreased with a decrease in [Ca]_o. However, below 0.7 mM [Ca]_o, the amplitude of observed IPSCs (excluding failures) reached a steady 'minimum' level. The meah conductance of the 'minimum' IPSCs measured in 0.5 mM [Ca]_o was 650 pS, which was comparable to the conductance of spontaneous miniature IPSCs recorded from motoneurones under tetrodotoxin. It is suggested that the 'minimum' IPSCs observed at low [Ca]_o may represent the quantal IPSCs. The quantal IPSCs had a coefficient of variation of 0.50 on average. The mean amplitude of quantal IPSCs varied among different motoneuromes by a factor of 3. No correlation was observed between the rise time and amplitude of quantal IPSCs, indicating that the dispersion in quantal size is not due to different locations of release sites. The statistical nature of the IPSCs indicated that the amplitude of IPSCs cannot be fitted with a binomial distribution. It is concluded that the quantal size constututing IPSCs may not be uniform at individual inhibitory synapses of neonatal rat spinal cord.

抑制性突触后电流（IPSC）的紧密全细胞记录是由新生大鼠脊柱运动神经元制成的。通过细胞外刺激单一的内沟神经元来唤起IPSC。当在各种频率（0.2-50 Hz）刺激时，从刺激伪像到IPSC发作的潜伏期是稳定的，平均潜伏期在37 C时为0.6-0.8 ms，这表明IPSCS的单突触性质。当减少外部Ca^<2+>浓度（[CA] _O）时，IPSC的故障数量增加，IPSC的平均幅度减少。 [CA] _O（0.35-1.4mm）与IPSC的平均幅度之间的关系是线性的，平均斜率在双对数坐标上为3.1。 IPSC的幅度随[Ca] _o的降低而降低。但是，低于0.7 mm [Ca] _o，观察到的IPSC（不包括故障）的幅度达到了稳定的“最小值”水平。以0.5 mm [Ca] _o测得的“最小” IPSC的MEAH电导率为650 PS，这与四毒素下的运动神经元记录的自发微型IPSC的电导率相当。建议在低[CA] _O处观察到的“最小” IPSC可能代表量子IPSC。量子IPSC的系数平均为0.50。量子IPSC的平均幅度在不同的运动瘤之间变化了3倍。在量化量IPSC的上升时间和幅度之间未观察到相关性，这表明量子大小的分散体并不是由于释放位点的不同位置所致。 IPSC的统计性质表明，IPSC的幅度不能拟合二项式分布。得出的结论是，在新生大鼠脊髓的个体抑制突触下，稳固的IPSC的量子大小可能不均匀。

项目成果

Takahashi,T.: "Membrane currents in Disvally identified motoreuroves of neonatal rat spiral cord." Journal of Physology (London). 423. 27-46 (1990)

Takahashi,T.：“迪斯瓦利鉴定出新生大鼠螺旋索运动细胞中的膜电流。”

Takahashi, T. & Berger, A. J.: "Direct excitation of rat spinal motoneurones by serotonin." Journal of Physiology (London). 423. 63-76 (1990)

高桥，T.

Berger, A. J. & Takahashi, T.: "Serotonin enhances a low-voltage-activated calcium current inrat spinal motoneurons." The Journal of Neuroscience. 10. 1922-1928 (1990)

伯杰，A.J.

Takahashi,T.& Berger,A.J.: "Direct excitation of rat spinal motoneurones by serotonin." Journal of Physiology(London). 423. 63-76 (1990)

高桥，T.

Takahashi,T.: "Inhibitory transmitterーgated ion channels in spinal motoneurones." Abstracts of the Annual Meeting of the European Neuroscience Association(Turin). 2. 31.3- (1989)

Takahashi, T.：“脊髓运动神经元中的抑制性递质门控离子通道。”欧洲神经科学协会年会摘要（都灵）2. 31.3-（1989）。