Calcium control of transmitter release at a cerebellar synapse

Neuron. 1995 Sep;15(3):675-88. doi: 10.1016/0896-6273(95)90155-8.


The manner in which presynaptic Ca2+ influx controls the release of neurotransmitter was investigated at the granule cell to Purkinje cell synapse in rat cerebellar slices. Excitatory postsynaptic currents were measured using whole-cell voltage clamp, and changes in presynaptic Ca2+ influx were determined with the Ca(2+)-sensitive dye furaptra. We manipulated presynaptic Ca2+ entry by altering external Ca2+ levels and by blocking Ca2+ channels with Cd2+ or with the toxins omega-conotoxin GVIA and omega-Aga-IVA. For all of the manipulations, other than the application of omega-Aga-IVA, the relationship between Ca2+ influx and release was well approximated by a power law, n approximately 2.5. When omega-Aga-IVA was applied, release appeared to be more steeply dependent on Ca2+ (n approximately 4), suggesting that omega-Aga-IVA-sensitive channels are more effective at triggering release. Based on interactive effects of toxins on synaptic currents, we conclude that multiple types of Ca2+ channels synergistically control individual release sites.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Benzofurans
  • Cadmium / pharmacology
  • Calcium / metabolism*
  • Calcium / pharmacology
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels / physiology*
  • Cerebellum / physiology*
  • Electric Conductivity
  • Fluorescent Dyes
  • Fura-2* / analogs & derivatives*
  • Neurotransmitter Agents / metabolism*
  • Oxazoles
  • Peptides / pharmacology
  • Purkinje Cells / physiology
  • Rats
  • Spider Venoms / pharmacology
  • Synapses / physiology*
  • omega-Agatoxin IVA
  • omega-Conotoxin GVIA


  • Benzofurans
  • Calcium Channel Blockers
  • Calcium Channels
  • Fluorescent Dyes
  • Neurotransmitter Agents
  • Oxazoles
  • Peptides
  • Spider Venoms
  • omega-Agatoxin IVA
  • Cadmium
  • 2-(2-(5-carboxy)oxazole)-5-hydroxy-6-aminobenzofuran-N,N,O-triacetic acid
  • omega-Conotoxin GVIA
  • Calcium
  • Fura-2