Multiple Calcium Channel Types Control Glutamatergic Synaptic Transmission in the Hippocampus

Neuron. 1993 Nov;11(5):895-902. doi: 10.1016/0896-6273(93)90119-c.

Abstract

N-type calcium channels play a dominant role in controlling synaptic transmission in many peripheral neurons. Transmitter release from mammalian central nerve terminals, however, is relatively resistant to the N channel antagonist omega-conotoxin GVIA. We studied the sensitivity of glutamatergic synaptic transmission in rat hippocampal slices to omega-conotoxin and to omega-Aga-IVA, a P channel antagonist. Both toxins reduced the amplitude of excitatory postsynaptic potentials in CA1 pyramidal neurons, but omega-Aga-IVA was the more rapid and efficacious. These results were corroborated by biochemical studies measuring subsecond, calcium-dependent [3H]glutamate release from hippocampal synaptosomes. Thus, at least two calcium channel types trigger glutamate release from hippocampal neurons, but P-type plays a more prominent role. Eliminating synaptic transmission in the CNS, therefore, may require inhibiting more than a single calcium channel type.

Publication types

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

MeSH terms

  • Animals
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels / physiology*
  • Glutamates / metabolism
  • Glutamates / physiology*
  • Glutamic Acid
  • Hippocampus / metabolism
  • Hippocampus / physiology*
  • Peptides / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Spider Venoms / pharmacology
  • Synapses / physiology*
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology*
  • omega-Agatoxin IVA
  • omega-Conotoxin GVIA

Substances

  • Calcium Channel Blockers
  • Calcium Channels
  • Glutamates
  • Peptides
  • Spider Venoms
  • omega-Agatoxin IVA
  • Glutamic Acid
  • omega-Conotoxin GVIA