DELAY IN VESICLE FUSION REVEALED BY ELECTROCHEMICAL MONITORING OF SINGLE SECRETORY EVENTS IN ADRENAL CHROMAFFIN CELLS
DELAY IN VESICLE FUSION REVEALED BY ELECTROCHEMICAL MONITORING OF SINGLE SECRETORY EVENTS IN ADRENAL CHROMAFFIN CELLS
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DOI：
10.1038/356060a0
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发表时间：
1992-03-05
期刊：
影响因子：
64.8
通讯作者：
NEHER, E
中科院分区：
文献类型：
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作者：
CHOW, RH;VONRUDEN, L;NEHER, E
在突触中，突触前细胞内钙的增加导致分泌小泡在不到一毫秒的时间内融合，从兴奋到突触后信号的短暂延迟就表明了这一点 1-4 。在非突触分泌细胞中，由于缺乏像突触后膜一样快速和灵敏的检测器，高时间分辨率的研究受到限制。电化学方法可能足够灵敏，可以检测单个囊泡释放的儿茶酚胺 5,6。在这里，我们表明，在电压钳条件下，可以使用碳纤维电极作为电化学检测器记录肾上腺嗜铬细胞随机发生的信号。这些信号服从量子释放的统计特征；然而，与神经元递质释放相反，短步去极化后分泌发生显着延迟。此外，我们在单一事件开始时识别出基座或“脚”，这可能代表儿茶酚胺分子在孔扩张以完成胞吐作用之前从狭窄的“融合孔”中缓慢泄漏。
IN synapses, a rise in presynaptic intracellular calcium leads to secretory vesicle fusion in less than a millisecond, as indicated by the short delay from excitation to postsynaptic signal 1-4 . In nonsynaptic secretory cells, studies at high time resolution have been limited by the lack of a detector as fast and sensitive as the postsynaptic membrane. Electrochemical methods may be sensitive enough to detect catecholamines released from single vesicles 5,6. Here, we show that under voltage-clamp conditions, stochastically occurring signals can be recorded from adrenal chromaffin cells using a carbon-fibre electrode as an electrochemical detector. These signals obey statistics characteristic for quantal release; however, in contrast to neuronal transmitter release, secretion occurs with a significant delay after short step depolarizations. Furthermore, we identify a pedestal or 'foot' at the onset of unitary events which may represent the slow leak of catecholamine molecules out of a narrow 'fusion pore' before the pore dilates for complete exocytosis.