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Updated: Aug 11, 2026

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration
Published on: July 31, 2013
Multiple calcium channel types control glutamatergic synaptic transmission in the hippocampus
J I Luebke1, K Dunlap, T J Turner
1Department of Physiology, Tufts University School of Medicine, Boston, Massachusetts 02111.
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.
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