Alcohol – How It Works
“I drink to make other people more interesting.” —Ernest Hemingway
What We Were Taught In School
Most of were taught in middle or high school that alcohol is a depressant (hopefully from a health class and not firsthand experience). Classic symptoms of drunkenness like slurred speech, impaired coordination, and diminished cognitive ability buttress that claim. And at very high doses, alcohol is lethal because it depresses nerve functioning in the brain stem to the point where your breathing stops.
What They Didn’t Teach Us (But Know From Experience)
But now that we’re older and have had the chance to experience the effects of alcohol firsthand, this simple statement doesn’t make much sense. If alcohol really was simply a depressant, everyone at a bar or club drinking would look and act like zombies – moving slowly, bumping into each other, and talking incoherently. Oh wait, that happens too. But more often than not, intoxication from alcohol evokes boisterousness, talkativeness, aggression, ribaldry, and other behaviors that are more typical of a stimulant than a depressant. The standard explanation for these effects is that alcohol depresses the “higher” cognitive abilities, such as the ability to control emotions, thus allowing our more unruly, carnal sides to emerge, and while this explanation contains a grain of truth, it undoubtedly misses the mark on what is truly occurring inside your body. In reality, alcohol is not a depressant with apparent stimulating attributes – it directly stimulates the brain and exerts a host of complicated effects, which we’ll talk about below.
The Missing Lecture in Our High School Biology Class
How does alcohol, or more specifically, ethanol, produces both stimulating and depressing effects? The answer lies in ethanol’s molecular structure.
Ethanol is a wondrous molecule. Its molecular structure makes it both water and fat soluble, allowing it barrage your body from multiple points. Because it dissolves easily in water, it is rapidly absorbed from the digestive tract and mixes easily with blood. Because it also dissolves in fats, it freely passes through the cell membrane’s phospholipid bilayer, which is practically a double-walled bubble of fat, and disrupts the glutamate receptors of neuronal cells. These two features are the key in understanding how and why we become intoxicated.
It’s true that alcohol—especially at moderate to high doses—can act as a general anesthetic, depressing a broad range of central nervous system functions. But alcohol also mimics the effects of cocaine, amphetamine, and opium. Like these stimulants, the ethanol molecule directly stimulates certain brain cells which causes the brain to release more dopamine, a neurotransmitter associated with wide range of effects (but most notably associated with pleasure in the pleasure/reward circuit of the brain), and causes our heart rate and blood pressure to rise.
At low doses, it increases electrical activity in the same brain systems affected by these classic stimulants and can lead to feelings of pleasure and euphoria because it releases our internal stores of the morphine-like compounds called endorphins. These neurochemicals work in conjunction with the brain’s core pleasure circuits, giving alcohol its addictive potential.
Interestingly enough, alcohol also works on exactly the same brain circuits targeted by Valium; the calming, anxiety-easing effects of alcohol closely resemble those exerted by this famous tranquilizer, which is why alcohol is sometimes described as a social lubricant.
But as you drink more and more and your body becomes inundated with alcohol, the ethanol molecules that escape destruction in your liver rush up to the brain through your blood stream. There, they bind to glutamate receptors and dampen glutamate’s capability to “fire” messages normally. This is the primary reason why you become “dumber” and “slower”. By inhibiting the brain’s ability to send messages from one neuron to another, alcohol effectively slows down activity in many parts of the brain. If the neurons in the affected areas control muscles, the inhibition can lead to relaxation and impaired coordination. If the neurons control speech, words slur and become increasingly imprecise. If the neurons control automatic bodily functions, heart rate and breathing are impaired. Studies have found that after consumption of two drinks in the space of one hour, glutamate receptor function can be reduced by more than 80 percent.
Substances such as cocaine and LSD work like pharmacological scalpels, altering the functioning of only one or a handful of brain circuits. Alcohol is more like a pharmacological hand grenade, affecting practically everything around it. This broad scope, in fact, sets alcohol apart from many other drugs. It’s a stimulating, depressing, and mood-altering drug that is a far more complex and interesting drug than most people give it credit for.
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