Visualization of Ca^<2+> in the presynaptic nerve terminal using a fast scan confocal microscope : Ca^<2+> microdomain and the short-term synaptic plastecity

使用快速扫描共聚焦显微镜观察突触前神经末梢 Ca^<2> 的可视化：Ca^<2> 微域和短期突触可塑性

• 批准号: 08680720
• 负责人: SUZUKI Naoya
• 金额: $ 1.6万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08680720/
• 关键词: Synapse; Neuro-muscular junction; Calcium sensitive dye; Calcium ion; Confocal microscope; Synaptic terminal; Synaptic plasticity

1. Ca^<2+> dynamics in the presynaptic terminalWe loaded Ca^<2+> sensitive dyes into presynaptic nerve-terminals of the frog neuro-muscular junction and measured Ca^<2+> dynamics during and after nerve stimulation. The free Ca^<2+> concentration rose about 1-2 muM during 10 stimulus st 100 Hz in a 1.8mM Ca^<2+> ringer solution. After the end of a tetanus, Ca^<2+> concentration declined quickly with a decay time constant about 50 ms and about 80% of rose Ca^<2+> was cleared within 200 ms. This indicate that rapid and high capacity Ca^<2+> clearance mechanism cxist in the presynaptic terminal. CCCP increased the Ca^<2+> concentration during tetanus and elongated the time constant of Ca^<2+> clearance. This indicates that the uptake of Ca^<2+> into mitochondria largely contributes as this Ca^<2+> clearance mechanism.2. Visualization of Ca^<2+> microdomainWe succeeded to take images of presynaptic Ca^<2+> dynamics with a time resolution of 2 ms. And we visualized the spatial heterogeneity of Ca^<2+> concentration in the terminal during increses transient phase of Ca^<2+> after a single nerve stimulation.3. The dependency of the facilitaion of transmitter release on presynaptic Ca^<2+> dynamicsWe investigated the effect of BAPTA-AM and EGTA-AM on the Ca^<2+> dynamics at the presynaptic terminal and the fast- and slow-facilitation of transmitter release after 10 tetanus at 100 Hz. BAPTA abolished the rapid Ca^<2+> transient and reduced the amplitade of fast-facilitation significantly. The slow kinetic Ca^<2+> -buffer, EGTA,reduced the amplitude of the rapid Ca^<2+> transient, but did not abolished in contrast to the case applied BAPTA.EGTA had a small effect on the amplitude of the fast-facilitation but shortened its time constant. EGTA reduced both the slow-facilitation and the show Ca^<2+> transient significantly. These results suggest a direct coupling between Ca^<2+> in nerve-terminal and the facilitation of transmitter releaes.

1.突触前末端的Ca^2+动态我们将Ca^2+敏感染料加载到青蛙神经肌肉接头的突触前神经末端，并测量神经刺激期间和之后的Ca^2+动态。在1.8mM Ca 2+ 林格溶液中，在10次10​​0Hz刺激期间，游离Ca 2+ 浓度上升约1-2μM。破伤风结束后，Ca^2+浓度迅速下降，衰减时间常数约为50ms，约80％的玫瑰Ca^2+在200ms内被清除。这表明突触前末梢存在快速、高容量的Ca^2+清除机制。 CCCP增加了破伤风期间的Ca^2+浓度并延长了Ca^2+清除的时间常数。这表明线粒体对Ca^2+的摄取在很大程度上促成了这种Ca^2+清除机制。2． Ca^<2+> 微域的可视化我们成功拍摄了时间分辨率为 2 ms 的突触前 Ca^<2+> 动态图像。并观察了单次神经刺激后Ca^2+瞬时增加过程中末端Ca^2+浓度的空间异质性。3．递质释放促进对突触前 Ca^<2+> 动力学的依赖性我们研究了 BAPTA-AM 和 EGTA-AM 对突触前末端 Ca^<2+> 动力学的影响以及 100 Hz 破伤风 10 次后递质释放的快慢促进。 BAPTA消除了快速Ca^2+瞬变并显着降低了快速促进的幅度。慢动力学Ca^2+缓冲剂EGTA降低了快速Ca^2+瞬变的幅度，但与应用BAPTA的情况相比并没有消除。EGTA对快速促进的幅度影响较小，但缩短了其时间常数。 EGTA显着降低了慢速促进和显示的Ca 2+ 瞬变。这些结果表明神经末梢中的Ca 2+ 与递质释放的促进之间存在直接耦合。

项目成果

H.Kijima: "Facilitation" Clinical Neuroscience. 15-10. 18-21 (1997)

H.Kijima：“促进”临床神经科学。

S.Goshima: "Effect of alkali metal cations on the lavellar water receptor cell of the fleshfly,Boettchrisca peregrina." J.Insect Physiol.43・11. 1031-1038 (1997)

S.Goshima：“碱金属阳离子对肉蝇腹膜水受体细胞的影响”，J.Insect Physiol.43・11（1997）。

H.Kijima: "Ca^<2+> dynamics in the presynaptic nerve terminal" Clinical Calcium. 8-2. 14-23 (1998)

H.Kijima：“突触前神经末梢的 Ca^2 动力学”临床钙。

木島 博正: "シナプス前神経末端におけるカルシウムイオン動態" CLINICAL CALCIUM. 8・2. 14-23 (1998)

Hiromasa Kijima：“突触前神经末梢的钙离子动力学”CLINICAL CALCIUM 8・2（1998）。

小山内 実: "シナプス前末端内のカルシウム濃度の可視化とその時間変化" 生物物理. 37・5. 223-224 (1997)

小山内稔：“突触前末梢钙浓度及其时间变化的可视化”生物物理学37・5（1997）。