Role of ionotropic glutamate receptors in LTP in rat hippocampal CA1 oriens-lacunosum moleculare interneurons

Abstract

Event Abstract Back to Event Role of ionotropic glutamate receptors in LTP in rat hippocampal CA1 oriens-lacunosum moleculare interneurons Iris Oren1, Wiebke Nissen2, Dimitri M. Kullmann1, Peter Somogyi3 and Karri Lamsa2* 1 UCL Institute of Neurology, University College London, United Kingdom 2 Department of Pharmacology, Oxford University, United Kingdom 3 MRC Anatomical Neuropharmacology Unit, Oxford University, United Kingdom Some interneurons of the hippocampus exhibit NMDA receptor-independent long-term potentiation (LTP) that is induced by presynaptic glutamate release when the postsynaptic membrane potential is hyperpolarized. This ‘anti-Hebbian’ form of LTP is prevented by postsynaptic depolarization or by blocking AMPA and kainate receptors. Although both AMPA and kainate receptors are expressed in hippocampal interneurons, their relative roles in anti-Hebbian LTP are not known. Because interneuron diversity potentially conceals simple rules underlying different forms of plasticity, we focus on glutamatergic synapses onto a subset of interneurons with dendrites in stratum oriens and a main ascending axon that projects to stratum lacunosum-moleculare, the O-LM cells. We show that anti-Hebbian LTP in O-LM interneurons has consistent induction and expression properties, and is prevented by selective inhibition of AMPA receptors. The majority of the ionotropic glutamatergic synaptic current in these cells is mediated by inwardly rectifying Ca2+ -permeable AMPA receptors. Although GluR5-containing kainate receptors contribute to synaptic currents at high stimulus frequency, they are not required for LTP induction. Glutamatergic synapses on O-LM cells thus behave in a homogeneous manner, and exhibit LTP dependent on Ca2+-permeable AMPA receptors. Restricting attention to an identified pathway within the hippocampal inhibitory circuitry thus reveals a far more uniform pattern of synaptic physiology, pharmacology and plasticity than seen in the population of interneurons as a whole. Sampling across interneuron types could explain some of the heterogeneity reported in previous studies on plasticity in which interneuron types were not identified. Conference: 12th Meeting of the Hungarian Neuroscience Society, Budapest, Hungary, 22 Jan - 24 Jan, 2009. Presentation Type: Poster Presentation Topic: Research on the cerebral cortex and related structures Citation: Oren I, Nissen W, Kullmann DM, Somogyi P and Lamsa K (2009). Role of ionotropic glutamate receptors in LTP in rat hippocampal CA1 oriens-lacunosum moleculare interneurons. Front. Syst. Neurosci. Conference Abstract: 12th Meeting of the Hungarian Neuroscience Society. doi: 10.3389/conf.neuro.01.2009.04.210 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 06 Mar 2009; Published Online: 06 Mar 2009. * Correspondence: Karri Lamsa, Department of Pharmacology, Oxford University, Oxford, United Kingdom, klamsa@bio.u-szeged.hu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Iris Oren Wiebke Nissen Dimitri M Kullmann Peter Somogyi Karri Lamsa Google Iris Oren Wiebke Nissen Dimitri M Kullmann Peter Somogyi Karri Lamsa Google Scholar Iris Oren Wiebke Nissen Dimitri M Kullmann Peter Somogyi Karri Lamsa PubMed Iris Oren Wiebke Nissen Dimitri M Kullmann Peter Somogyi Karri Lamsa Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.