Letter abstract
Nature Cell Biology 5, 358 - 362 (2003)
Published online: 24 March 2003 | doi:10.1038/ncb956
There is an Erratum (May 2003) associated with this Letter.
Exocytosis of single chromaffin granules in cell-free inside-out membrane patches
Gregor Dernick1, Guillermo Alvarez de Toledo2 & Manfred Lindau1
In chromaffin cells, exocytosis of single granules and properties of the fusion pore — the first connection between vesicular lumen and extracellular space1 — can be studied by cell-attached patch amperometry2, 3, which couples patch-clamp capacitance measurements4, 5, 6, 7 with simultaneous amperometric recordings of transmitter release8, 9. Here we have studied exocytosis of single chromaffin granules and endocytosis of single vesicles in cell-free inside-out membrane patches by patch capacitance measurements and patch amperometry. We excised patches from chromaffin cells by using methods developed for studying properties of single ion channels10. With low calcium concentrations in the pipette and bath, the patches showed no spontaneous exocytosis, but exocytosis could be induced in some patches by applying calcium to the cytoplasmic side of the patch. Exocytosis was also stimulated by calcium entry through the patch membrane. Initial conductances of the fusion pore were undistinguishable in cell-attached and excised patch recordings, but the subsequent pore expansion was slower in excised patches. The properties of exocytotic fusion pores in chromaffin cells are very similar to those observed in mast cells and granulocytes. Excised patches provide a tool with which to study the mechanisms of fusion pore formation and endocytosis in vitro.
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York, 14853-2501, USA
- Department of Physiology and Biophysics, University of Seville, E-41009 Sevilla, Spain
Correspondence to: Manfred Lindau1 e-mail: ml95@cornell.edu
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