A membrane marker leaves synaptic vesicles in milliseconds after exocytosis in retinal bipolar cells

David Zenisek, Jürgen A. Steyer, Morris E. Feldman, Wolfhard Almers

Research output: Contribution to journalArticle

151 Scopus citations


Perhaps synaptic vesicles can recycle so rapidly because they avoid complete exocytosis, and release transmitter through a fusion pore that opens transiently. This view emerges from imaging whole terminals where the fluorescent lipid FM1-43 seems unable to leave vesicles during transmitter release. Here we imaged single, FM1-43-stained synaptic vesicles by evanescent field fluorescence microscopy, and tracked the escape of dye from single vesicles by watching the increase in fluorescence after exocytosis. Dye left rapidly and completely during most or all exocytic events. We conclude that vesicles at this terminal allow lipid exchange soon after exocytosis, and lose their dye even if they connected with the plasma membrane only briefly. At the level of single vesicles, therefore, observations with FM1-43 provide no evidence that exocytosis of synaptic vesicles is incomplete.

Original languageEnglish (US)
Pages (from-to)1085-1097
Number of pages13
Issue number6
Publication statusPublished - Sep 12 2002


ASJC Scopus subject areas

  • Neuroscience(all)

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