The following article first appeared at and was written by Jordan Gaines. We have included the section here that discusses the amino acid GABA, but please read the whole story to discover how alcohol mimics GABA amino acid in the brain.

When you take a swig of alcohol, it goes right into the bloodstream, and it’s in your brain within minutes.

Alcohol mimics gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the brain. When bound to a GABA receptor on a neuron, alcohol allows the influx of negative (or efflux of positive) ions, giving the cell a more negative charge. Thus, the neuron’s attempt to fire an action potential is thwarted.

Alcohol also inhibits the brain’s major excitatory neurotransmitter, glutamate, by blocking function at glutamate’s NMDA receptors.

Since glutamatergic and GABAergic neurons comprise 90 percent of all brain cells, this is a pretty big deal. Especially since alcohol also enhances GABA absorption back into the neuron, and even more especially since GABA is recycled into glutamate in a vicious cycle: After an evening of drinking, the theory is that GABA dominates the first half of the night, allowing us to fall asleep (and deeply!). But once GABA is metabolized, much of it becomes the excitatory glutamate. And it’s in glutamate-releasing brain regions (such as the reticular activating system which partially modulates sleep/wake and arousal) that the midnight disruptions kick in.