Action Potential-induced Quantal Secretion of Catecholamines from Rat Adrenal Chromaffin Cells

Using single rat adrenal chromaffin cells, we examined the coupling of action potential activity to quantal release of catecholamines by combining perforated patch current-clamp recording with electrochemical microcarbon fiber amperometry. Chromaffin cells display steeper dependence of quantal relea...

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Bibliographic Details
Published in:The Journal of biological chemistry 1995-02, Vol.270 (8), p.3498-3505
Main Authors: Zhou, Z, Misler, S
Format: Article
Language:English
Subjects:
Action Potentials
Adrenal Medulla - cytology
Adrenal Medulla - drug effects
Adrenal Medulla - metabolism
Adrenal Medulla - physiology
Animals
Catecholamines - metabolism
Cells, Cultured
Cholinergic Agents - pharmacology
Chromaffin Granules
Rats
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Summary:Using single rat adrenal chromaffin cells, we examined the coupling of action potential activity to quantal release of catecholamines by combining perforated patch current-clamp recording with electrochemical microcarbon fiber amperometry. Chromaffin cells display steeper dependence of quantal release on action potential frequency than many nerve terminals, as well as more desynchronized release following an action potential. Also in contrast to neurons, in chromaffin cells, a major chemical secretagogue (acetylcholine) triggers potent quantal release even in the absence of electrical activity. These findings are consistent with an hypothesis that a major component of exocytosis from chromaffin cells involves diffusion of Ca to secretion sites which are less well co-localized with Ca channels than those in nerve terminals.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.270.8.3498