Abstract
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 language | English (US) |
---|---|
Pages (from-to) | 20-24 |
Number of pages | 5 |
Journal | Biophysical Chemistry |
Volume | 123 |
Issue number | 1 |
DOIs | |
State | Published - Aug 20 2006 |
Bibliographical note
Funding Information:This work was supported by National Institutes of Health Grant NS 38879.
Keywords
- Amperometry
- CCCP
- Ca-induced Ca release
- Chromaffin cell
- Fura-2