Depression of glutamate and GABA release by presynaptic GABAB receptors in the entorhinal cortex in normal and chronically epileptic rats

Abstract

Presynaptic GABAB receptors (GABABR) control glutamate and GABA release at many synapses in the nervous system. In the present study we used whole-cell patch-clamp recordings of spontaneous excitatory and inhibitory synaptic currents in the presence of TTX to monitor glutamate and GABA release from synapses in layer II and V of the rat entorhinal cortex (EC)in vitro. In both layers the release of both transmitters was reduced by application of GABABR agonists. Quantitatively, the depression of GABA release in layer II and layer V, and of glutamate release in layer V was similar, but glutamate release in layer II was depressed to a greater extent. The data suggest that the same GABABR may be present on both GABA and glutamate terminals in the EC, but that the heteroreceptor may show a greater level of expression in layer II. Studies with GABABR antagonists suggested that neither the auto- nor the heteroreceptor was consistently tonically activated by ambient GABA in the presence of TTX. Studies in EC slices from rats made chronically epileptic using a pilocarpine model of temporal lobe epilepsy revealed a reduced effectiveness of both auto- and heteroreceptor function in both layers. This could suggest that enhanced glutamate and GABA release in the EC may be associated with the development of the epileptic condition. Copyright © 2006 S. Karger AG.

Publication DOI: https://doi.org/10.1159/000098515
Divisions: College of Health & Life Sciences > Aston Pharmacy School
College of Health & Life Sciences > Clinical and Systems Neuroscience
College of Health & Life Sciences > Aston Institute of Health & Neurodevelopment (AIHN)
College of Health & Life Sciences
Additional Information: CC BY-NC 3.0
Uncontrolled Keywords: entorhinal cortex,epilepsy,GABA release,GABA receptors,glutamate release,Neuroscience(all)
Publication ISSN: 1424-8638
Last Modified: 29 May 2024 07:07
Date Deposited: 10 Feb 2015 15:45
Full Text Link: http://www.karg ... /FullText/98515
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2007-06
Authors: Thompson, Sarah E.
Ayman, Göher
Woodhall, Gavin L. (ORCID Profile 0000-0003-1281-9008)
Jones, Roland S.G.

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