Two-photon imaging of spontaneous vesicular release in acute brain slices and its modulation by presynaptic GABAA receptors
Two-photon imaging of spontaneous vesicular release in acute brain slices and its modulation by presynaptic GABAA receptors
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DOI：
10.1016/j.neuroimage.2004.02.009
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发表时间：
2004-06-01
期刊：
影响因子：
5.7
通讯作者：
Müller, W
中科院分区：
文献类型：
--
作者：
Axmacher, N;Winterer, J;Müller, W
γ -氨基丁酸（GABA）在中枢神经系统中非动作电位自发囊泡释放介导微型抑制性突触后电流（mIPSCs），并对中枢兴奋性起重要控制作用。利用双光子激光扫描显微镜和高渗加载易释放的囊泡池与荧光苯乙烯染料FM1-43在海马片，我们证明了动作电位不依赖的囊泡释放（荧光染色）从近端周围，假设的GABA能终端和特异性GABA(A)受体激动剂muscimol显著抑制这种释放存在河豚毒素和谷氨酸受体拮抗剂CNQX和AP5。这些数据与CA3锥体神经元全细胞记录中muscimol对mIPSCs的减少一致。相比之下，远端（可能是谷氨酸末端）的囊泡释放率明显较低，且不受muscimol的影响。在缺乏外源钙的情况下，muscimol对mIPSCs的作用不会被阻断，反而会增强。我们的数据直接证明了GABAA受体激活对GABA释放的有效去抑制性减少。这些新方法应该很好地适用于研究癫痫患者神经外科治疗切除后抑制的病理生理变化。(C) 2004爱思唯尔公司版权所有。
Action potential-independent spontaneous vesicular release of gamma-aminobutyric acid (GABA) in the CNS mediates miniature inhibitory postsynaptic currents (mIPSCs) and exerts an important control on central excitability. Using dual-photon laser scan microscopy and hyperosmotic loading of the readily releasable vesicle pool with the fluorescent styryl dye FM1-43 in hippocampal slice, we demonstrate action potential-independent release of vesicles (fluorescence destaining) from proximal perisomatic, presumed GABAergic terminals and significant inhibition of this release by the specific GABA(A) receptor agonist muscimol in the presence of tetrodotoxin and glutamate receptor antagonists CNQX and AP5. These data agree with reduction of mIPSCs by muscimol in whole-cell recordings from CA3 pyramidal neurons. In contrast, rate of vesicle release from distal, presumably glutamatergic terminals, was significantly lower and not changed by muscimol. The effect of muscimol on mIPSCs was not blocked but rather enhanced in the absence of external calcium. Our data directly demonstrate a potent disinhibitory reduction of GABA release by GABAA receptor activation. Those novel methods should be well suite to study pathophysiological changes in inhibition in resections obtained from neurosurgical treatment of epilepsy patients. (C) 2004 Elsevier Inc. All rights reserved.