PT  - JOURNAL ARTICLE
AU  - Yi Shen
AU  - A Kerstin Lindemeyer
AU  - Igor Spigelman
AU  - Werner Sieghart
AU  - Richard W Olsen
AU  - Jing Liang
TI  - Plasticity of GABA<sub>A</sub> Receptors Following Ethanol Pre-exposure in Cultured Hippocampal Neurons
AID  - 10.1124/mol.110.068650
DP  - 2010 Jan 01
TA  - Molecular Pharmacology
PG  - mol.110.068650
4099  - http://molpharm.aspetjournals.org/content/early/2010/12/16/mol.110.068650.short
4100  - http://molpharm.aspetjournals.org/content/early/2010/12/16/mol.110.068650.full
AB  - Alcohol use causes many physiological changes in brain with behavioral sequelae. We previously observed (Liang et al., 2007) plastic changes in hippocampal slices recordings paralleling behavioral changes in rats treated with a single intoxicating dose of ethanol (EtOH). Here, we were able to reproduce in primary cultured hippocampal neurons many of the effects of in vivo EtOH exposure on GABAA receptors (GABAARs). Cells grown 11-15 days in vitro (DIV) demonstrated GABAAR δ subunit expression and sensitivity to enhancement by acute EtOH (60 mM) of GABAAR-mediated tonic current (Itonic) using whole-cell patch-clamp techniques. EtOH gave virtually no enhancement of mIPSCs. Cells pre-exposed to EtOH (60 mM) for 30 min showed, 1 h after EtOH withdrawal, a 50% decrease in basal Itonic magnitude and tolerance to acute EtOH enhancement of Itonic, followed by reduced basal mIPSC area at 4 h. At 24 h, we saw considerable recovery in mIPSC area and significant potentiation by acute EtOH; also, GABAAR currents exhibited reduced enhancement by benzodiazepines. These changes paralleled significant decreases in cell-surface expression of normally extrasynaptic δ and α4 GABAAR subunits as early as 20 min after EtOH exposure, reduced α5-containing GABAARs at 1 h, followed by a larger reduction of normally synaptic α1 subunit at 4 h, followed by increases in α4γ2-containing cell-surface receptors by 24 h. Measuring internalization of biotinylated GABAARs, we showed for the first time that the EtOH-induced loss of Itonic and cell-surface δ/α4 20 min after withdrawal results from increased receptor endocytosis rather than decreased exocytosis.