Vesicular Ca2+-induced secretion promoted by intracellular pH-gradient disruption

Christy L. Haynes, Leah A. Buhler, R. Mark Wightman

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


The actions of the protonophore CCCP on intracellular Ca2+ regulation and exocytosis in chromaffin cells have been examined. Simultaneous fura-2 imaging and amperometry reveal that exposure to CCCP not only perturbs mitochondrial function but that it also alters vesicular storage of Ca2+ and catecholamines. By disrupting the pH gradient of the secretory vesicle membrane, the protonophore allows both Ca2+ and catecholamine to leak into the cytosol. Unlike the high cytosolic Ca2+ concentrations resulting from mitochondrial membrane disruption, Ca2+ leakage from secretory vesicles may initiate exocytotic release. In conjunction with previous studies, this work reveals that catalytic and self-sustained vesicular Ca2+-induced exocytosis occurs with extended exposure to weak acid or base protonophores.

Original languageEnglish (US)
Pages (from-to)20-24
Number of pages5
JournalBiophysical Chemistry
Issue number1
StatePublished - Aug 20 2006

Bibliographical note

Funding Information:
This work was supported by National Institutes of Health Grant NS 38879.


  • Amperometry
  • CCCP
  • Ca-induced Ca release
  • Chromaffin cell
  • Fura-2


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