Chromaffin cell cortical actin network dynamics control the size of the release-ready vesicle pool and the initial rate of exocytosis

Neuron. 1995 Feb;14(2):353-63. doi: 10.1016/0896-6273(95)90291-0.


Morphological, biochemical, and membrane capacitance measurements were used to study the role of cortical filamentous actin (F-actin) in exocytosis. Fluorescence and electron microscopy of resting chromaffin cells revealed a cortical actin network that excluded secretory vesicles from the subplasmalemmal area. Phorbol ester (PMA) treatment disrupted cortical F-actin and increased both the number of vesicles within the 0-50 nm subplasmalemmal zone and the initial rate of stimulated catecholamine release. In PMA-pretreated cells, membrane capacitance studies showed an increased number of vesicles fusing with the plasmalemma during the first two depolarizations of a train. PMA did not affect voltage-dependent Ca2+ influx. The total number of vesicles fused with the plasma membrane correlated well with the number of vesicles occupying the 0-50 nm cortical zone. Therefore, cortical F-actin disassembly allows translocation of vesicles to the plasmalemma in preparation for exocytosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / drug effects
  • Actins / metabolism*
  • Actins / ultrastructure
  • Adrenal Cortex / drug effects
  • Adrenal Cortex / physiology*
  • Adrenal Cortex / ultrastructure
  • Animals
  • Cattle
  • Cell Membrane / physiology
  • Cell Membrane / ultrastructure
  • Cells, Cultured
  • Chromaffin Granules / drug effects
  • Chromaffin Granules / physiology
  • Chromaffin Granules / ultrastructure*
  • Electrophysiology / methods
  • Epinephrine / metabolism
  • Exocytosis*
  • Kinetics
  • Membrane Potentials
  • Microscopy, Electron
  • Nicotine / pharmacology
  • Norepinephrine / metabolism
  • Potassium / pharmacology
  • Tetradecanoylphorbol Acetate / pharmacology
  • Video Recording


  • Actins
  • Nicotine
  • Tetradecanoylphorbol Acetate
  • Potassium
  • Norepinephrine
  • Epinephrine