Alcohol will make you laugh or it may cause you to cry, it may cause you to lively or cause you to sleepy, it may boost your confidence or make you act the fool. How can alcohol have all these different effects on people? If we want to understand how alcohol affects our moods and behaviors we must first understand a bit about how the brain works.
A persons mental abilities are made up of about 100 billion nerve cells (also known as neurons). Everything that we think, feel or do may be the consequence of electrical signals passing backwards and forwards between neurons. These electrical signals require the help of chemicals called neurotransmitters in order to pass from neuron to neuron. Scientists have identified around 60 different neurotransmitters so far and inform us that there are probably a lot more yet to be identified.
Different neurotransmitters have different effects in the brain. For example, serotonin is connected with mood. People struggling with clinical depression generally have a shortage of serotonin within their brains, and medications like Prozac can help to alleviate depression by helping the availability of serotonin within the brain. Endorphins are a class of neurotransmitters which behave as the brain’s natural painkillers.
Electrical signals in the brain are transmitted in the following manner: The neuron which is sending the electrical signal releases a neurotransmitter, and also the neuron that is receiving the electrical signal accepts the neurotransmitter in a site which is called a receptor. When the neurotransmitter from the first neuron chemically binds towards the receptor from the second neuron the electrical signal is transmitted. Neurotransmitters and receptors work like locks and keys: there’s a minumum of one different receptor for every different neurotransmitter. For instance, an endorphin receptor are only able to be triggered by and endorphin, a serotonin receptor can only be triggered by serotonin, and so on. Different neurons have different receptors. Some neurons are only triggered by serotonin, some only by an endorphin, and so forth for the different neurotransmitters.
Okay–now exactly what does all of this have to do with alcohol?
Every mood altering substance from heroin to coffee impacts the neurotransmitter system of the brain. Some psychoactive drugs affect just one specific neurotransmitter system, whereas others affect many. Morphine, for instance, mimics the neurotransmitter beta-endorphin–a natural painkiller based in the brain. Morphine is shaped like beta-endorphin and binds to the beta-endorphin receptors thus acting as a painkiller and also giving rise to feelings of pleasure. Caffeine is in the shape of Adenosine and acts about the adenosine receptors. Alcohol on the other hand affects many different neurotransmitters, not just one, Why?
Morphine and caffeine are generally large molecules. Neurotransmitters are also large molecules. Morphine and caffeine have the effects that they do due to their similarity in shape to neurotransmitters which occur naturally in the brain. Alcohol on the other hand is really a quite small molecule. Alcohol does not mimic a neurotransmitter. So then how does alcohol affect neurotransmitters?
Alcohol is a fat soluble molecule. Fats (called lipids) are a major component of all cell membranes, including the cell membranes of neurons. Alcohol enters the cell membranes of neurons and changes their properties. Receptors can be found on cell membranes which implies that receptor properties are altered through the presence of alcohol. Cell membranes also control the discharge of neurotransmitters and this implies that the release of neurotransmitters can also be affected by the existence of alcohol.
The effects of alcohol on receptors and neurotransmitters happen to be well documented for many neurotransmitters as well as their corresponding receptors. These effects are summarized in Table 1.
Table 1: Alcohol’s Impact on Neurotransmitters and Receptors
Glutamate
Alcohol inhibits glutamate receptor function
This causes muscular relaxation, discoordination, slurred speech, staggering, memory disruption, and blackouts
Ether and chloroform have similar effects about the glutamate system
GABA (gamma-aminobutyric acid)
Alcohol enhances GABA receptor function
This causes feelings of calm, anxiety-reduction and sleep
Valium has a similar impact on the GABA system
Dopamine
Alcohol raises dopamine levels
This results in excitement and stimulation
Cocaine and amphetamine have similar effects on the dopamine system
Endorphins
Alcohol raises endorphin levels
This kills pain and results in an endorphin “high”
Morphine and heroin have similar effects on the endorphin system
Drugs like morphine or cocaine happen to be referred to as “chemical scalpels” because of their very precise effects on just one neurotransmitter system. Alcohol however is much more like a chemical hand grenade for the reason that it affects just about all areas of the brain and all sorts of neurotransmitter systems. Alcohol affects each one of these systems simultaneously. When people consume alcohol they become lively and excited because alcohol raises dopamine levels just as cocaine does, although alcohol doesn’t raise dopamine levels anywhere close to much as cocaine does. When people drink alcohol they think calm and lose their anxieties because alcohol makes the GABA receptors function more proficiently just like valium does. The reason that people tend to fall asleep after drinking alcohol or taking valium can also be due to this effect on the GABA receptor. And alcohol has a painkilling effect like morphine and produces a high much like morphine since it leads to a discharge of endorphins in to the brain thus raising the endorphin levels. (Note that the result of morphine differs from alcohol in the mechanism–morphine imitates endorphins and binds to endorphin receptors whereas alcohol boosts the levels of the endorphins within the brain.) Finally we come to glutamate. Alcohol greatly inhibits the functioning of the glutamate receptor. Glutamate is responsible for the development of recent memories and for muscular coordination. It is alcohol’s impact on the glutamate receptor which leads to slurred speech, and staggering in those who have consumed alcohol, along with the inability to remember what one did that night when the morning after comes. Probably the only positive effect of the effect on the glutamate receptor is a feeling of muscular relaxation. Many unwanted effects of alcohol for example automobile fatalities due to driving under the influence would be the consequence of losing coordination caused by alcohol’s impact on the glutamate receptor. Even small quantities of alcohol possess a major effect on coordination–so never, never drive after drinking.
You have probably observed that alcohol has different effects on differing people. Some people become sleepy after drinking slightly alcohol whereas others become animated and want to go, go, go. Research on mice suggests that this difference is genetic. Scientists happen to be able to breed strains of mice which quickly fall asleep after ingesting alcohol. They have been able to breed strains of mice which become very active after ingesting alcohol. This strongly shows that genetics determines which neurotransmitter system is most strongly impacted by alcohol in which individual. Individuals who become sleepy right after drinking probably get their GABA system more strongly affected by alcohol. And folks who become lively and excited after drink probably get their dopamine system most strongly affected.
The results of alcohol about the brain do not end when alcohol is totally metabolized and out of the system–what happens next is one thing called neurotransmitter rebound. This rebound effect is most easily illustrated if we take a look at what goes on to a lot of people once they make use of a drink or two like a sleep aid. These folks often often awaken in the middle of the night time and find themselves not able to fall back asleep. What’s happening is this–alcohol has enhanced the functioning of the GABA system and it has made these people feel relaxed and sleepy. The whole time that alcohol is present the GABA system is struggling to overcome the results of alcohol and return to normal functioning. When all of the alcohol is finally from the body, the GABA system overshoots the mark and leaves people feeling restless and wide awake. This is why alcohol is not a good sleep aid. Large quantities of alcohol can keep an individual asleep longer, but drinking large quantities of alcohol has its own negative effects. Neurotransmitter rebound seems and to be implicated in the signs of hangovers such as hyper-sensitivity to light as well as in alcohol withdrawal syndrome giving rise to feelings of tension and panic and other symptoms too.
Some medications used to treat alcohol abuse for example campral and naltrexone work by affecting the neurotransmitter systems. Naltrexone (also called revia) is an opioid receptor antagonist. Naltrexone functions by binding towards the endorphin receptors (which are sometimes also called opioid receptors) and blocking them off to ensure that opiates cannot bind to these receptors. Unlike opiates or endorphins naltrexone doesn’t have painkilling effects with no pleasurable effects. Naltrexone simply blocks off the endorphin receptors to ensure that neither opiates nor endorphins might have their painkilling or pleasurable effects. Naltrexone is highly effective with individuals who use opiates such as morphine or heroin as these drugs have no effect at all once the receptors are blocked by naltrexone. Naltrexone has some effect in assisting individuals to abstain from alcohol in order to moderate their use, yet it’s less effective with alcohol as with opiates because alcohol affects many different neurotransmitters. The downside of naltrexone would be that the body’s natural painkillers, the endorphins, are unable to get the job done when it’s present. People taking naltrexone are advised to wear medic-alert bracelets so that doctors knows that painkillers are ineffective on these folks.
Campral (also called acamprosate) is really a glutamate receptor modulator. Campral helps eliminate cravings for alcohol in long-term heavy drinkers. It’s hypothesized that long-term heavy drinking upsets the glutamate neurotransmitter system which campral helps you to restore this to normalcy.
No discussion of alcohol and also the brain would be complete without a mention of possible brain damage brought on by excessive drinking. Chances are that we have all heard that drinking kills brain cells. However, does scientific evidence bear out this common folk saying? A 1993 study by Jensen and Pakkenberg published in Lancet titled “Do alcoholics drink their neurons away?” compared the brains of alcoholics towards the brains of non-alcoholics. This study found that the white few the brains of alcoholics was significantly depleted. The gray matter, however, was exactly the same in both alcoholics and non-alcoholics. This really is interesting since it is the gray matter that does the thinking. The gray matter continues to be compared to a network of computers, and the white matter to the cables linking them together. The mind doesn’t produce new gray matter to exchange what is lost. The brain can, however, produce new white matter to replace white matter which has been lost. The researchers concluded that lack of white matter do to heavy drinking it will not constitute irreparable damage.
There’s, however, a form of irreparable brain damage which can be brought on by long-term heavy drinking. This really is Wernicke-Korsakoff Syndrome, also called “wet brain”. Wernicke-Korsakoff Syndromeis not the result of a lack of brain cells–it is caused by a lack of vitamin B1 (also known as thiamine). Wernicke-Korsakoff Syndrome can have several causes including extreme malnutrition, prolonged periods of vomiting because of morning sickness or an eating disorders, kidney dialysis, stomach stapling, or alcohol abuse. Most cases of Wernicke-Korsakoff Syndrome which exist in the United States come from severe, long-term, heavy drinking. Alcohol can result in Wernicke-Korsakoff Syndrome since it blocks the absorption of thiamine. Symptoms of Wernicke-Korsakoff Syndrome include amnesia, inability to form new memories, confusion, hallucinations, and confabulation. A few of the worse symptoms of Wernicke-Korsakoff Syndrome can be treated with thiamine, in many instances most of the symptoms persist for life.
Have scientists discovered everything that there is to know about alcohol’s effects about the brain? It seems that this really is clearly not the case. Scientists think that alcohol likely affects a lot more neurotransmitters compared to four discussed in this article. There’s constant and ongoing research to find out how alcohol might affect other neurotransmitters. The future is likely to bring us much new understanding of alcohol and the brain.