Sombers L A, Hanchar H J, Colliver T L, Wittenberg N, Cans A, Arbault S, Amatore C, Ewing A G
Department of Chemistry, 152 Davey Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802-6300, USA.
J Neurosci. 2004 Jan 14;24(2):303-9. doi: 10.1523/JNEUROSCI.1119-03.2004.
Many spikes in amperometric records of exocytosis events initially exhibit a prespike feature, or foot, which represents a steady-state flux of neurotransmitter through a stable fusion pore spanning both the vesicle and plasma membranes and connecting the vesicle lumen to the extracellular fluid. Here, we present the first evidence indicating that vesicular volume before secretion is strongly correlated with the characteristics of amperometric foot events. L-3,4-dihydroxyphenylalanine and reserpine have been used to increase and decrease, respectively, the volume of single pheochromocytoma cell vesicles. Amperometry and transmission electron microscopy have been used to determine that as vesicle size is decreased the frequency with which foot events are observed increases, the amount and duration of neurotransmitter released in the foot portion of the event decreases, and vesicles release a greater percentage of their total contents in the foot portion of the event. This previously unidentified correlation provides new insight into how vesicle volume can modulate the activity of the exocytotic fusion pore.
胞吐作用事件的安培记录中的许多尖峰最初都呈现出峰前特征，即足，它代表神经递质通过跨越囊泡和质膜并连接囊泡腔与细胞外液的稳定融合孔的稳态通量。在此，我们提供了首个证据，表明分泌前的囊泡体积与安培足事件的特征密切相关。L-3,4-二羟基苯丙氨酸和利血平已分别用于增加和减少单个嗜铬细胞瘤细胞囊泡的体积。通过安培法和透射电子显微镜已确定，随着囊泡尺寸减小，观察到足事件的频率增加，事件足部释放的神经递质的量和持续时间减少，并且囊泡在事件足部释放其总内容物的比例更大。这种先前未被识别的相关性为囊泡体积如何调节胞吐融合孔的活性提供了新的见解。
