Aguilar Jenny I, Dunn Matthew, Mingote Susana, Karam Caline S, Farino Zachary J, Sonders Mark S, Choi Se Joon, Grygoruk Anna, Zhang Yuchao, Cela Carolina, Choi Ben Jiwon, Flores Jorge, Freyberg Robin J, McCabe Brian D, Mosharov Eugene V, Krantz David E, Javitch Jonathan A, Sulzer David, Sames Dalibor, Rayport Stephen, Freyberg Zachary
Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.
Department of Chemistry, Columbia University, New York, NY 10027, USA.
Neuron. 2017 Aug 30;95(5):1074-1088.e7. doi: 10.1016/j.neuron.2017.07.038. Epub 2017 Aug 17.
The ability of presynaptic dopamine terminals to tune neurotransmitter release to meet the demands of neuronal activity is critical to neurotransmission. Although vesicle content has been assumed to be static, in vitro data increasingly suggest that cell activity modulates vesicle content. Here, we use a coordinated genetic, pharmacological, and imaging approach in Drosophila to study the presynaptic machinery responsible for these vesicular processes in vivo. We show that cell depolarization increases synaptic vesicle dopamine content prior to release via vesicular hyperacidification. This depolarization-induced hyperacidification is mediated by the vesicular glutamate transporter (VGLUT). Remarkably, both depolarization-induced dopamine vesicle hyperacidification and its dependence on VGLUT2 are seen in ventral midbrain dopamine neurons in the mouse. Together, these data suggest that in response to depolarization, dopamine vesicles utilize a cascade of vesicular transporters to dynamically increase the vesicular pH gradient, thereby increasing dopamine vesicle content.
突触前多巴胺末梢调节神经递质释放以满足神经元活动需求的能力对神经传递至关重要。尽管囊泡内容物一直被认为是静态的，但体外数据越来越表明细胞活动会调节囊泡内容物。在这里，我们在果蝇中使用协调的遗传学、药理学和成像方法来研究负责体内这些囊泡过程的突触前机制。我们表明，细胞去极化通过囊泡超酸化在释放前增加突触囊泡多巴胺含量。这种去极化诱导的超酸化由囊泡谷氨酸转运体（VGLUT）介导。值得注意的是，在小鼠腹侧中脑多巴胺神经元中也观察到了去极化诱导的多巴胺囊泡超酸化及其对VGLUT2的依赖性。总之，这些数据表明，响应去极化时，多巴胺囊泡利用一系列囊泡转运体来动态增加囊泡pH梯度，从而增加多巴胺囊泡含量。
