Alcohol acts on many neuroreceptor systems and, as already mentioned, alcohol addiction differs from other addictions in that it has no known receptor system in the brain. It also alters the activity of serotonin receptors (5 HT3). Additionally it acts on the nicotinic receptors. It modifies the γ-aminobutyric acid (GABA)ergic neurotransmitter (type A: GABA-A), which is an inhibitory neurotransmitter, and also acts on the N-methyl-D-aspartic acid (NMDA) receptors of glutaminergic neurotransmission and on the NMDA subgroups on the glutaminergic receptor-stimulating neurotransmitter. Furthermore alcohol inhibits the δ-opiate receptors while long-term exposure to the alcohol increases the density of μ and δ receptors and generally increases endogenous opiate levels in opioid neurotransmission [23,24].
