The exocytotic event in chromaffin cells revealed by patch amperometry

A. Albillos, G. Dernick, H. Horstmann, W. Almers, G. Alvarez de Toledo, M. Lindau

Research output: Contribution to journalArticlepeer-review

453 Scopus citations

Abstract

In mast cells and granulocytes, exocytosis starts with the formation of a fusion pore. It has been suggested that neurotransmitters may be released through such a narrow pore without full fusion. However, owing to the small size of the secretory vesicles containing neurotransmitter, the properties of the fusion pore formed during Ca2+-dependent exocytosis and its role in transmitter release are still unknown. Here we investigate exocytosis of individual chromaffin granules by using cell-attached capacitance measurements combined with electrochemical detection of catecholamines, achieved by inserting a carbon-fibre electrode into the patch pipette. This allows the simultaneous determination of the opening of individual fusion pores and of the kinetics of catecholamine release from the same vesicle. We found that the fusion-pore diameter stays at <3 nm for a variable period, which can last for several seconds, before it expands. Transmitter is released much faster through this pore than in mast cells, generating a 'foot' signal which precedes the amperometric spike. Occasionally, the narrow pore forms only transiently and does not expand, allowing complete transmitter release without full fusion of the vesicle with the plasma membrane.

Original languageEnglish (US)
Pages (from-to)509-512
Number of pages4
JournalNature
Volume389
Issue number6650
DOIs
StatePublished - Oct 22 1997

ASJC Scopus subject areas

  • General

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