Neal M J, Bowery N G
Brain Res. 1979 May 11;167(2):337-43. doi: 10.1016/0006-8993(79)90827-8.
The effect of veratridine and potassium depolarization on the release of [3H]GABA from neural tissues in which GABA uptake is neuronal (cerebrocortical slices and frog retina) or glial (rat retina, spinal and sympathetic ganglia) was studied. The 'neuronal' but not the 'glial' release of [3H]GABA was greatly increased by KC1 (25 mM) and veratridine (10 microM). The 'neuronal' release of [3H]GABA evoked with KC1 was calcium dependent but the small potassium induced increase in 'glial' release were not reduced in the absence of calcium ions even when additional Mg2+ was included in the medium. Surprisingly, the veratridine induced release of [3H]GABA from cortical slices was greatly potentiated in calcium free medium although the release of [3H]noradrenaline produced by veratridine was calcium dependent. Because of the insensitivity of the glial GABA release mechanism to potassium depolarization, it is concluded that release of endogenous GABA from glial pools in response to physiological increases in extracellular potassium is unlikely to be important.
研究了藜芦碱和钾离子去极化对[3H]γ-氨基丁酸（GABA）从GABA摄取为神经元性（大脑皮质切片和蛙视网膜）或胶质细胞性（大鼠视网膜、脊髓和交感神经节）的神经组织中释放的影响。氯化钾（25 mM）和藜芦碱（10 μM）可显著增加[3H]GABA的“神经元性”而非“胶质细胞性”释放。氯化钾诱发的[3H]GABA的“神经元性”释放依赖于钙，但即使在培养基中加入额外的镁离子，在无钙离子的情况下，钾离子诱导的“胶质细胞性”释放的少量增加也不会减少。令人惊讶的是，尽管藜芦碱产生的[3H]去甲肾上腺素的释放依赖于钙，但在无钙培养基中，藜芦碱诱导的大脑皮质切片中[3H]GABA的释放却大大增强。由于胶质细胞GABA释放机制对钾离子去极化不敏感，因此得出结论，在细胞外钾离子生理性增加时，胶质细胞池中内源性GABA的释放不太可能起重要作用。
