Ca(2+)-independent but voltage-dependent secretion in mammalian dorsal root ganglion neurons

Nat Neurosci. 2002 May;5(5):425-30. doi: 10.1038/nn845.


We have investigated the Ca(2+) dependence of vesicular secretion from the soma of dorsal root ganglion (DRG) neurons, which secrete neuropeptides by exocytosis of dense-core vesicles. In patch-clamped somata of rat DRG neurons, we found a depolarization-induced membrane capacitance increase (DeltaC(m)) in the absence of extracellular Ca(2+) and in the presence of a Ca(2+) chelator (BAPTA) in the intracellular solution. Depletion of internal Ca(2+) stores by thapsigargin in the Ca(2+)-free bath also did not block the DeltaC(m), indicating that Ca(2+) release from internal Ca(2+) stores may not have been involved. Furthermore, the Ca(2+)-independent DeltaC(m) was blocked by whole-cell dialysis with tetanus toxin and was accompanied by pulsatile secretion of false transmitters, as detected by amperometric measurements. These results indicate the existence of Ca(2+)-independent but voltage-dependent vesicular secretion (CIVDS) in a mammalian sensory neuron.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology
  • Adenosine Triphosphate / pharmacology
  • Anesthetics, Local / pharmacology
  • Animals
  • Cadmium / pharmacology
  • Calcium / metabolism*
  • Calcium Channel Blockers / pharmacology
  • Cell Membrane / physiology
  • Cell Separation
  • Chelating Agents / pharmacology
  • Egtazic Acid / analogs & derivatives*
  • Egtazic Acid / pharmacology
  • Electric Capacitance
  • Electric Stimulation
  • Exocytosis / drug effects
  • Exocytosis / physiology
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / drug effects
  • Ganglia, Spinal / metabolism*
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / metabolism*
  • Neuropeptides / metabolism
  • Patch-Clamp Techniques
  • Rats
  • Secretory Vesicles / metabolism
  • Tetanus Toxin / pharmacology


  • Anesthetics, Local
  • Calcium Channel Blockers
  • Chelating Agents
  • Neuropeptides
  • Tetanus Toxin
  • Cadmium
  • Egtazic Acid
  • Adenosine Triphosphate
  • 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid
  • Calcium