Quantal size is dependent on stimulation frequency and calcium entry in calf chromaffin cells
Quantal size is dependent on stimulation frequency and calcium entry in calf chromaffin cells
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DOI：
10.1016/s0896-6273(01)00418-4
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发表时间：
2001-09-13
期刊：
影响因子：
16.2
通讯作者：
Artalejo, CR
中科院分区：
文献类型：
--
作者：
Elhamdani, A;Palfrey, HC;Artalejo, CR
递质释放的量子假说在多大程度上适用于致密核囊泡（DCV）分泌尚不清楚。我们用儿茶酚胺电流分析法结合不同的刺激模式来确定小牛嗜铬细胞中单个分泌事件的特征。在2 mM [Ca 2 +]（o）或在7 Hz下从0.25-7 mM [Ca 2 +]（o）中从0.25-10 Hz提高动作电位序列的频率提高了每个事件释放的量（量子大小）。随着刺激的增加，量子尺寸连续上升，而不是突然上升，这表明从一个单一的人口的DCV，而不是招聘不同大小的囊泡的释放效率的影响。这些结果表明，儿茶酚胺分泌不符合量子模型。抑制快速内吞阻尼分泌连续发作，这意味着一个重要的作用，这个过程中需要连续分泌的囊泡的回收。
To what extent the quantal hypothesis of transmitter release applies to dense-core vesicle (DCV) secretion is unknown. We determined the characteristics of individual secretory events in calf chromaffin cells using catecholamine amperometry combined with different patterns of stimulation. Raising the frequency of action potential trains from 0.25-10 Hz in 2 mM [Ca2+](o) or [Ca2+](o) from 0.25-7 mM at 7 Hz elevated the amount released per event (quantal size). With increased stimulation, quantal size rose continuously, not abruptly, suggesting that release efficiency from a single population of DCVs rather than recruitment of different-sized vesicles contributed to the effect. These results suggest that catecholamine secretion does not conform to the quantal model. Inhibition of rapid endocytosis damped secretion in successive episodes, implying an essential role for this process in the recycling of vesicles needed for continuous secretion.