Alcohol disturbs the neurochemistry of the brain, primarily causing an increase of “inhibitory” signals between brain cells. This causes the physical manifestations of being intoxicated, such as loss of balance, low muscle coordination, and memory loss.
What is the first picture that comes to mind when you hear the word “party”?
“Partying” and celebratory events almost always involve drinking. Humans commonly view alcohol as an aid for socialization with family and peers, or even with strangers.
If you’ve seen someone drunk, you know that alcohol can obviously alter our behavior in various ways, but how does it happen? And what happens to our brain to achieve these effects?
To understand the mechanism of alcohol, we must first explore how brain cells communicate.
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The chemistry within the human brain
The human brain is simply a huge mass of nerve cells that talk to each other through electrical signals. Additionally, there are chemical messengers called “neurotransmitters” in the brain. Each neuron stores these chemicals in small vesicles near its tail end. It releases these chemical “bags” when it sends a signal to its next cell. These chemicals then go and bind to sites on the next neuron, causing it to either send a signal or not.
These neurotransmitters have specific actions when they bind to proteins called “receptors” in nerve cells, similar to how a key fits into a lock.
A neurotransmitter can either “excite” the nerve cell, making them send a signal, or they “depress” or inhibit the nerve cell from sending a signal.
A good example of an “excitatory” chemical is glutamate, while GABA (Gamma-aminobutyric acid) is an “inhibitory” neurochemical.
Some parts of the brain are specific in their choice of neurotransmitters. For example, cells in a region called substantia nigra employ dopamine for signaling. Therefore, they are called “dopaminergic” neurons. Other parts of the brain have a mixture of cells that employ different types of neurotransmitters.
Mechanism of action of alcohol in the brain
When we consume alcohol, it reaches our bloodstream after some time and then reaches our brain as blood circulates through the body. In the brain, it binds to a variety of receptors of neurotransmitters, leading to diverse effects. Mainly, it binds to receptors of GABA, an inhibitory neurotransmitter, and decreases the responsiveness of nerve cells. This type of overall reduction in brain activity is called “central nervous system (CNS) depression”.
In addition, it also causes a similar inhibitory action in the spinal cord and the lower part of the brain, called the brain stem. It does this by interfering with the receptors of a neurotransmitter called “glycine”. Together, these lead to an overall relaxed state of being. The muscle movements of the person slow down, pupils relax, breathing slows, and there may be confusion and dizziness. Of these, the most notable effect is a lowering of social inhibition, allowing us to behave in ways that we typically wouldn’t.
In addition to inhibitory action, alcohol also reduces the action of excitatory neurons, creating a sedative effect.
Alcohol acts on the cerebellum, a part of the brain that helps to coordinate movements, resulting in a decreased ability to coordinate muscle movements while walking, talking, etc.
Short-term and long-term effects
Alcohol consumption, as we noted earlier, interferes with several neurotransmitters in the brain and affects their interactions with brain cells. Alcohol is reported to have several damaging effects on the brain, both in the short and long term.
Studies have shown that alcohol consumption, even over the short term, can impact memory by interfering and damaging the mechanism of memory formation, which occurs in a seahorse-shaped region called the “hippocampus” in the brain (Source).
Under normal conditions, the human brain maintains a good balance between excitatory and inhibitory chemicals. When we consume alcohol, this balance is disturbed, resulting in more overall inhibitory chemical signaling in the brain. However, when it comes to the short-term use of alcohol, this balance will be restored after some time and the effects are usually reversible.
However, with long-term use of alcohol, this balance can get distorted permanently, which can lead to “tolerance”. In such cases, individuals become less responsive to small amounts of alcohol over time. This often results in people consuming even greater amounts of alcohol.
Addiction to alcohol
Alcohol can provide many short-term effects that people find rewarding, which can then motivate people to consume alcohol more often. With long-term use, abstaining from alcohol can cause discomfort or “withdrawal”.
These effects go away as soon as an alcoholic consumes alcohol. This is a vicious cycle, resulting in alcoholics seeking alcohol more and more frequently.
Alcohol causes addiction through complex mechanisms involving multiple neurotransmitters in the brain. One example is dopamine, which signals and helps us feel a sense of “reward” in response to an action. Humans tend to repeat rewarding actions. Therefore, addiction can easily occur by modifying the action of dopamine in the brain, among other chemicals.
Alcohol consumption is a part of socialization in many cultures. It is also widely represented in books, movies, and social media. However, very little effort is spent in understanding the darker side—what consuming alcohol does to our bodies and brains.
Alcohol affects signaling between cells in the brain in various ways. This results in an altered mental state, changed behavior, and various effects on the body. It may have many effects that are considered desirable, such as lowering social inhibition. Most of us know that addiction and long-term use is harmful to our body, but even short-term consumption has been shown to cause long-lasting damage in research studies. It is important to remember that the seemingly harmless effects of drinking are achieved by interfering with a multitude of brain chemicals and altering the normal functioning of the brain. In other words, proceed with caution!