A hebbian form of long-term potentiation dependent on mGluR1a in hippocampal inhibitory interneurons.
Hippocampal inhibitory interneurons play important roles in controlling the excitability and synchronization of pyramidal cells, but whether they express long-term synaptic plasticity that contributes to hippocampal network function remains uncertain. We found that pairing postsynaptic depolarization with theta-burst stimulation induced long-term potentiation (LTP) of putative single-fiber excitatory postsynaptic currents in interneurons. Either postsynaptic depolarization or theta-burst stimulation alone failed to induce LTP. LTP was expressed as a decrease in failure rates and an increase in excitatory postsynaptic current amplitude, independent of N-methyl-d-aspartate receptors, and dependent on metabotropic glutamate receptors subtype 1a. LTP was induced specifically in interneurons in stratum oriens and not in interneurons of stratum radiatum/lacunosum-moleculare. Thus, excitatory synapses onto specific subtypes of inhibitory interneurons express a new form of hebbian LTP that will contribute to hippocampal network plasticity.
Perez
Y
Y
Département de Physiologie, Centre de Recherche en Sciences Neurologiques, Université de Montréal, Case Postale 6128, Succursale Centre-ville, Montréal, QC, Canada H3C 3J7.
Morin
F
F
Lacaille
J C
JC
D000818:Animals; D019706:Excitatory Postsynaptic Potentials; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D066298:In Vitro Techniques; D007395:Interneurons / Q000502:physiology*; D017774:Long-Term Potentiation; D051381:Rats; D018094:Receptors, Metabotropic Glutamate / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology
D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C104077:metabotropic glutamate receptor type 1