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Altering the concentration of GABA in the synaptic cleft potentiates miniature IPSCs in rat occipital cortex
Author(s) -
Perrais David,
Ropert Nicole
Publication year - 2000
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2000.00957.x
Subject(s) - gabaa receptor , postsynaptic potential , neurotransmission , chemistry , biophysics , cortex (anatomy) , dextran , inhibitory postsynaptic potential , neuroscience , receptor , biology , biochemistry
Abstract We have tested the effect of dextran (40 kDa, 5%) on miniature IPSCs (mIPSCs) recorded in layer V cortical pyramidal cells. This compound increases the amplitude of mIPSCs at room and physiological temperatures by 15%, leaving their duration unaffected at room temperature and slightly increased at physiological temperature. The amplitude increase is attributable to an increase in the number of receptors bound by GABA during synaptic transmission, as shown by the occlusion between the effects of dextran and zolpidem on mIPSC amplitude at room temperature. As dextran presumably enhances the concentration and dwell time of GABA in the synaptic cleft, these results demonstrate that the postsynaptic GABA A receptors are not saturated at room and physiological temperatures.