One of the earlier patch clamp studies performed in cultured mouse hippocampal neurons determined that concentrations of 40mM ethanol potentiated GABA-gated current, and that increasing concentrations up to 80mM were ineffective in producing further potentiation [27]. Other early work utilizing whole–cell patch clamp recordings in rat hippocampal CA1 neurons showed that 10–50mM concentrations of ethanol enhanced GABA-A receptor mediated fast IPSCs, and that the concentration-dependence of IPSC enhancement constituted a bell-shaped curve, with significant potentiation at 10mM, peaking at 20mM [28]. However, it must be stated that there have been many negative findings over the years in studies that have attempted to repeat thee observations. The results of these investigations underscore the importance of using physiologically relevant ethanol concentrations when studying hippocampal excitability and plasticity in response to acute ethanol.
