Alcohol binds to receptor sites for several neurotransmitters, including acetylcholine, serotonin, and GABA.  GABA, a neural inhibitor that plays an active role in impulse transmission, has receptor sites on the post synaptic neuron.  Alcohol’s presence in the GABA receptor site results in a sustained conformational change in the channel protein, allowing excess chloride ions into the cell.  This effectively hyperpolarizes the cell, reducing the chance that the threshold potential will be reached.  Subsequently, action potentials fire less readily, and the neural networks usually in place are disrupted.