Alcohol is one of the most widely used psychoactive substances in the world, and has been a part of different cultures for hundreds of years.
Drinking alcohol can have serious harmful consequences, it’s been linked to various cancers, gastrointestinal diseases, and metabolic problems.
Over time, regular use of alcohol can lead to alcohol dependence and bouts of withdrawal, and this can take a serious physical and emotional toll on a person’s life.
Alcoholic drinks contain the chemical ethanol, which is a tiny molecule that reduces the activity of various inhibitory and excitatory neurotransmitter pathways in the brain.
Inhibitory neurotransmitters make neurons in the central nervous system less likely to fire an action potential, and the brain’s major inhibitory neurotransmitter—gamma-aminobutyric acid or GABA—acts as an “off” switch and restricts brain activity.
Ethanol is a GABA agonist, so when it binds to GABA receptors it makes that inhibitory signal even stronger.
Ethanol also activates opioid receptors and induces the release of endogenous morphine—known as endorphins.
The opioids then bind to receptors on dopaminergic neurons in the nucleus accumbens, which trigger the release of dopamine and serotonin in that part of the brain.
Ethanol also acts as a glutamate antagonist.
In other words, ethanol blocks glutamate, which is an excitatory neurotransmitter, from binding to glutamate receptors, making it less likely that those neurons will fire.
The combined effect that ethanol has on these neurotransmitters varies by the location in the brain.
For example, in the nucleus accumbens and the amygdala, which are the reward centers of the brain, ethanol produces pleasant or rewarding feelings like euphoria.
This is important because if a person believes that drinking leads to euphoria, they are more likely to drink again.
In the cerebral cortex, the thought-processing center of the brain, ethanol slows everything down, making it difficult to think and speak clearly.