In cultured cortical neurons from rats, maximal GABA response potentiation was achieved at 50 mM ethanol [44]. In contrast, GABA current inhibition was seen at 40–50 mM ethanol in cultured chick neurons. In the rat medial frontal cortex, it has been demonstrated that the rate of spontaneous GABA-mediated inhibitory postsynaptic currents (sIPSCs) is unchanged by 50 mM ethanol, indicating that ethanol does not increase GABA release from presynaptic terminals onto these neurons [14]. Another area of focus has been the effect of ethanol on “persistent activity” in the prefrontal cortex. In slice co-cultures of PFC neurons, it has been shown that concentrations of 25 mM inhibit persistent activity, measured as a reduction in upstate amplitude, duration, and number of spikes per up-state [45]. Other studies have examined the effects of ethanol on persistent activity in pyramidal neurons and fast-spiking GABAergic interneurons. Using a slice co-culture system, it was shown that 44 mM ethanol significantly reduced the average duration of up-states in both types of neuron and had a variable effect on spiking, with a trend towards an increase in pyramidal
