Jensen K, Lambert J D, Jensen M S
Department of Physiology, University of Aarhus, DK-8000 C, Aarhus, Denmark.
Brain Res. 2000 Oct 13;880(1-2):198-201. doi: 10.1016/s0006-8993(00)02746-3.
Asynchronous GABA release was studied in cultured hippocampal neurons using paired whole-cell recordings. Tetanization of the presynaptic GABAergic neuron was accompanied by a train of IPSCs which showed tetanic depression. Asynchronous IPSCs (asIPSCs) also developed during the train and continued for 1.85+/-0.3 s after the stimulation. The threshold frequency for evoking asIPSCs was 10 Hz, while maximal asynchronous activity was achieved at 40 Hz. Perfusion with EGTA-AM blocked asIPSCs. The elevation of Ca(2+) that accompanies presynaptic action potential firing triggers asynchronous release of GABA vesicles, thereby counteracting tetanic depression of synchronous IPSCs.
使用配对全细胞记录法在培养的海马神经元中研究了异步γ-氨基丁酸（GABA）释放。对突触前GABA能神经元进行强直刺激时伴随着一串抑制性突触后电流（IPSCs），这些电流表现出强直抑制。在强直刺激过程中也会出现异步IPSCs（asIPSCs），并且在刺激后持续1.85±0.3秒。诱发asIPSCs的阈值频率为10赫兹，而在40赫兹时达到最大异步活动。用乙二醇双（2-氨基乙基醚）四乙酸-乙酰甲酯（EGTA-AM）灌注可阻断asIPSCs。突触前动作电位发放所伴随的细胞内钙离子浓度（Ca(2+)）升高会触发GABA囊泡的异步释放，从而抵消同步IPSCs的强直抑制。
