Mechanisms determining the time course of secretion in neuroendocrine cells

Neuron. 1996 Feb;16(2):369-76. doi: 10.1016/s0896-6273(00)80054-9.


Transmitter release from chromaffin cells differs from that in synapses in that it persists for a longer time after Ca2+ entry has stopped. This prolonged secretion is not due to a delay between vesicle fusion and transmitter release, nor to slow detection of released substance: step increases in capacitance due to single vesicle fusion precede the release detected by amperometry by only a few milliseconds. The persistence of secretion after a depolarization is reduced by addition of mobile calcium buffer. This suggests that most of the delay is due to diffusion of Ca2+ between channels and release sites, implying that Ca2+ channels and secretory vesicles are not colocalized in chromaffin cells, in contrast to presynaptic active zones.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenal Glands / cytology
  • Adrenal Glands / metabolism*
  • Adrenal Glands / physiology
  • Animals
  • Buffers
  • Calcium
  • Cattle
  • Chelating Agents / pharmacology
  • Chromaffin System / cytology
  • Chromaffin System / metabolism*
  • Chromaffin System / physiology
  • Electric Conductivity
  • Electrophysiology
  • Fura-2 / pharmacology
  • Nystatin / pharmacology
  • Reaction Time
  • Time Factors


  • Buffers
  • Chelating Agents
  • Nystatin
  • Calcium
  • Fura-2