title: Enhancement of CA3 hippocampal network activity by activation of group II metabotropic glutamate receptors.
abstract: Impaired function or expression of group II metabotropic glutamate receptors (mGluRIIs) is observed in brain disorders such as schizophrenia. This class of receptor is thought to modulate activity of neuronal circuits primarily by inhibiting neurotransmitter release. Here, we characterize a postsynaptic excitatory response mediated by somato-dendritic mGluRIIs in hippocampal CA3 pyramidal cells and in stratum oriens interneurons. The specific mGluRII agonists DCG-IV or LCCG-1 induced an inward current blocked by the mGluRII antagonist LY341495. Experiments with transgenic mice revealed a significant reduction of the inward current in mGluR3(-/-) but not in mGluR2(-/-) mice. The excitatory response was associated with periods of synchronized activity at theta frequency. Furthermore, cholinergically induced network oscillations exhibited decreased frequency when mGluRIIs were blocked. Thus, our data indicate that hippocampal responses are modulated not only by presynaptic mGluRIIs that reduce glutamate release but also by postsynaptic mGluRIIs that depolarize neurons and enhance CA3 network activity.
authors.affiliation: Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland.
authors.forename: Jeanne
authors.initials: J
authors.lastname: Ster
authors.forename: José María
authors.initials: JM
authors.lastname: Mateos
authors.forename: Benjamin Friedrich
authors.initials: BF
authors.lastname: Grewe
authors.forename: Guyllaume
authors.initials: G
authors.lastname: Coiret
authors.forename: Corrado
authors.initials: C
authors.lastname: Corti
authors.forename: Mauro
authors.initials: M
authors.lastname: Corsi
authors.forename: Fritjof
authors.initials: F
authors.lastname: Helmchen
authors.forename: Urs
authors.initials: U
authors.lastname: Gerber
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D056654:CA3 Region, Hippocampal / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D003521:Cyclopropanes / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D007395:Interneurons / Q000378:metabolism / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D008854:Microscopy, Electron; D009415:Nerve Net / Q000378:metabolism / Q000502:physiology*; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics / Q000502:physiology*; D013826:Theta Rhythm / Q000187:drug effects / Q000502:physiology; D014966:Xanthenes / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D003521:Cyclopropanes; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; C114624:LY 341495; D018094:Receptors, Metabotropic Glutamate; D014966:Xanthenes; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3; C082313:2-(2,3-dicarboxycyclopropyl)glycine; D005998:Glycine