Limberger N, Späth L, Starke K
J Neurochem. 1986 Apr;46(4):1102-8. doi: 10.1111/j.1471-4159.1986.tb00624.x.
The release of gamma-aminobutyric acid (GABA) was studied in slices of the head of the rabbit caudate nucleus. The slices were preincubated with [3H]GABA and then superfused. Aminooxyacetic acid was present throughout. Both the tritium in the slices and that in the superfusate consisted practically entirely of [3H]GABA. Stimulation for 2 min by electrical field pulses of 3 ms width and 9 V/cm voltage drop (36 mA current strength) at 5 or 20 Hz elicited an overflow of [3H]GABA that amounted to 0.23 or 0.47% of the tritium content of the tissue, respectively, and was diminished by 85% in the presence of tetrodotoxin. At higher current strength, less of the stimulation-evoked overflow was tetrodotoxin-sensitive. cis-1,3-Aminocyclohexane carboxylic acid diminished the uptake of [3H]GABA into the tissue but did not change the percentage released by electrical stimulation. Ca2+ withdrawal greatly accelerated basal [3H]GABA efflux and almost abolished the response to stimulation. Nipecotic acid 10-1,000 microM enhanced both the basal and (up to eightfold) the stimulation-evoked overflow. The method described allows us to elicit electrically a quasiphysiological, i.e., Ca2+-dependent and tetrodotoxin-sensitive, neuronal release of [3H]GABA. Nipecotic acid diverts released [3H]GABA from reuptake to overflow.
在兔尾状核头部切片中研究了γ-氨基丁酸（GABA）的释放。将切片用[³H]GABA预孵育，然后进行灌流。全程加入氨基氧乙酸。切片中的氚和灌流液中的氚几乎完全由[³H]GABA组成。以5或20Hz的频率施加宽度为3ms、电压降为9V/cm（电流强度36mA）的电场脉冲刺激2分钟，分别引起[³H]GABA溢出量相当于组织中氚含量的0.23%或0.47%，且在存在河豚毒素时减少85%。在较高电流强度下，刺激诱发的溢出中对河豚毒素敏感的部分较少。顺式-1,3-氨基环己烷羧酸减少了[³H]GABA进入组织的摄取，但未改变电刺激释放的百分比。去除Ca²⁺极大地加速了基础[³H]GABA外流，并几乎消除了对刺激的反应。10 - 1000μM的哌啶酸增强了基础和刺激诱发的溢出（最多增加八倍）。所描述的方法使我们能够通过电刺激诱发准生理性的、即依赖Ca²⁺且对河豚毒素敏感的神经元释放[³H]GABA。哌啶酸使释放的[³H]GABA从再摄取转向溢出。
