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Early expression of KCC2 in rat hippocampal cultures augments expression of functional GABA synapses
Author(s) -
Chudotvorova Ilona,
Ivanov Anton,
Rama Sylvain,
Hübner Christian A.,
Pellegrino Christophe,
BenAri Yehezkel,
Medina Igor
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2005.089821
Subject(s) - excitatory postsynaptic potential , inhibitory postsynaptic potential , gabaergic , glutamate receptor , postsynaptic potential , ampa receptor , neuroscience , cotransporter , postsynaptic density , silent synapse , postsynaptic current , gabaa receptor , biology , chemistry , receptor , biochemistry , organic chemistry , sodium
The development of GABAergic synapses is associated with an excitatory to inhibitory shift of the actions of GABA because of a reduction of [Cl − ] i . This is due to a delayed postnatal expression of the K + –Cl − cotransporter KCC2, which has low levels at birth and peaks during the first few postnatal weeks. Whether the expression of the cotransporter and the excitatory to inhibitory shift have other consequences on the operation of GABA A receptors and synapses is not yet known. We have now expressed KCC2 in immature neurones at an early developmental stage and determined the consequences on the formation of GABA and glutamate synapses. We report that early expression of the cotransporter selectively enhances GABAergic synapses: there is a significant increase of the density of GABA A receptors and synapses and an increase of the frequency of GABAergic miniature postsynaptic currents. The density of glutamate synapses and frequency of AMPA miniature postsynaptic currents are not affected. We conclude that the expression of KCC2 and the reduction of [Cl − ] i play a critical role in the construction of GABAergic networks that extends beyond the excitatory to inhibitory shift of the actions of GABA.