Extracellular ATP Regulates the Vesicular Pore Opening in Chromaffin Cells and Increases the Fraction Released During Individual Exocytosis Events
Extracellular ATP Regulates the Vesicular Pore Opening in Chromaffin Cells and Increases the Fraction Released During Individual Exocytosis Events
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DOI：
10.1021/acschemneuro.8b00722
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发表时间：
2019-05-01
影响因子：
5
通讯作者：
Ewing, Andrew G.
中科院分区：
文献类型：
--
作者：
Majdi, Soodabeh;Larsson, Anna;Ewing, Andrew G.
三磷酸腺苷（ATP）是细胞代谢的主要能量来源。此外，ATP是一种神经递质和共递质，作用于突触前或突触后的嘌呤能受体。几乎所有类型的分泌囊泡从任何神经元或动物物种含有高浓度的ATP，是一个重要的因素，在积累的神经递质。本工作研究了ATP对嗜铬细胞量子儿茶酚胺释放和囊泡贮存的影响。我们结合了三种电化学方法：传统安培法与细胞内囊泡撞击电化学细胞术和囊泡撞击电化学细胞术。我们发现细胞外ATP增加了儿茶酚胺释放的量子分数，但没有增加其囊泡含量。研究ATP处理的细胞中的胞吐事件的动力学表明，ATP影响释放融合孔。为了阐明所观察到的ATP效应的机制，用苏拉明（一种嘌呤能阻断剂）和ARL-67156（一种外ATP酶的拮抗剂）对细胞和囊泡进行连续处理。数据表明，与对照组相比，这些药物后囊泡的儿茶酚胺含量增加。我们的数据表明，作用于嘌呤能受体的ATP通过增加融合孔开放增加了量子可释放的大小，并且ARL-67156和/或苏拉明通过作为ATP的竞争性抑制剂起作用来保护囊泡免受神经递质泄漏。
Adenosine triphosphate (ATP) is the main energy source for cellular metabolism. Besides that, ATP is a neurotransmitter and a cotransmitter that acts on purinergic receptors present either' pre- or postsynaptically. Almost all types of secretory vesicles from any neuron or animal species contain high concentrations of ATP, being an essential factor in the accumulation of neurotransmitters. In this work, we studied the effects of ATP on quantum catecholamine release and vesicular storage in chromaffin cells. We combined three electrochemical methods: conventional amperometry with intracellular vesicle impact electrochemical cytometry and vesicle impact electrochemical cytometry. We found that extracellular ATP increased the released quantal fraction of catecholamine but not its vesicular content. Studying the dynamics of exocytosis events in ATP treated cells showed that ATP affects the release fusion pore. To elucidate the mechanisms of the observed ATP effects, cells and vesicles were pharmacologically treated with suramin (a purinergic blocker) and ARL-67156 (an antagonist of ecto-ATPases). The data indicate that the catecholamine content of vesicles increased compared to control after these drugs. Our data suggest that ATP acting on purinergic receptors increases the quantum releasable size through an increased fusion pore opening and that ARL-67156 and/or suramin protect the vesicle from neurotransmitter leakage by functioning as competitive inhibitors to ATP.