Schroeder T J, Borges R, Finnegan J M, Pihel K, Amatore C, Wightman R M
Department of Chemistry, University of North Carolina at Chapel Hill 27599-3290, USA.
Biophys J. 1996 Feb;70(2):1061-8. doi: 10.1016/S0006-3495(96)79652-2.
The stages of the complex events involved in exocytotic secretion after vesicle-cell membrane fusion have been examined at the level of individual vesicles. Catecholamine flux from single bovine adrenal medullary cells was measured with carbon-fiber microelectrodes firmly touching the cell surface. The data reveal that secretion during exocytotic events has three distinct stages: a small increase in catecholamine flux, a rapid, but not instantaneous, rise to a maximum, followed by an exponential decrease in the flux. These stages are interpreted in the following ways. The initial stage corresponds to catecholamine secretion through a fusion pore. The rate of pore expansion appears to control the rise time of the flux to its maximum value. The final exponential stage is consistent with chemical dissociation of the intravesicular matrix or gel.
在单个囊泡水平上，研究了囊泡与细胞膜融合后胞吐分泌所涉及的复杂事件的各个阶段。用牢固接触细胞表面的碳纤维微电极测量单个牛肾上腺髓质细胞的儿茶酚胺通量。数据显示，胞吐事件期间的分泌有三个不同阶段：儿茶酚胺通量略有增加，迅速但非瞬间升至最大值，随后通量呈指数下降。这些阶段可作如下解释。初始阶段对应于通过融合孔的儿茶酚胺分泌。孔扩张的速率似乎控制着通量上升到最大值的时间。最后的指数阶段与囊泡内基质或凝胶的化学解离一致。
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