If you’re reading this in the morning (I’m writing it in the morning, at least) then you’re probably already craving a cup of your favorite caffeinated beverage. But have you ever thought about exactly how that Caffeine works? How it functions inside your body? How it makes it to your brain?
We all have some idea of what Caffeine is. A drug. A chemical. The single most popular, widely-consumed psychotropic substance on the planet. Found naturally in the seeds, or leaves, of over sixty plants, notably coffee beans, tea leaves, and cocoa beans. It’s also an additive to many everyday products, including analgesics, cold medications, mouthwashes, and lotions. In the proper dosage, it drastically improves endurance, concentration, and reaction time. In improper dosage, provoking panic, anxiety, tremors, and dehydration.
But first, let me explain what Caffeine is, chemically: a Central Nervous Stimulant, of the Methylxanthine family of drugs, with a chemical formula of C8H10N4O2. It’s a psychoactive substance in the same way as THC, LSD, and all those other naughty three-letter words. But far less dramatic in its effects on perception and consciousness. Nevertheless: a drug which acts on both body and mind.
Like many psychotropics, it’s an alkaloid — one of many nitrogenous organic compounds, often of plant origin, which have pronounced physiological actions in the brains and bodies of humans. And while Caffeine, in particular, is usually consumed in beverage form – entering the bloodstream through the stomach lining, and crossing the blood-brain barrier to work on our receptors – pure Caffeine (in powder or pill form) can also be taken as a more powerful means of staying alert and focused – frequently as a way to legally improve athletic performance.
The physical effects come on quickly, and disappear with a similar rapidity. The palpable stimulation – its most noticeable psychoactive characteristic – comes from its ability to block the actions of adenosine in the brain. Adenosine, a chemical that transmits a “slow down” message from receptors to the central nervous system, is a compound that acts as a neuromodulator in the brain. It regulates the excitability of neurons controlling vital body functions and affects sleep, memory, learning, and mood. And by slowing down the nervous system, adenosine produces physical and mental lethargy, thus making it difficult for the body and brain to perform under normal conditions.
Caffeine removes this effect and results in the “lift” that users feel. In other words, caffeine blocks (or “antagonizes”) the receptors that recognize adenosine, preventing them from activating. This prevents or relieves the drowsiness and other symptoms of withdrawal from starting, effectively canceling them out. If a person is currently experiencing the effects of withdrawal (e.g., feelings of drowsiness), then only consumption of more Caffeine will relieve or prevent those symptoms from occurring.
And, if adenosine receptors are blocked, scientists have observed that the functions of other neurotransmitters also change. Glutamate and dopamine functioning, in particular, are enhanced as a result. Many pharmacologists believe that the adenosine modulation described above, along with the tertiary effects on dopamine and glutamate, combine to create the whole picture: the unmistakable excitement, increased energy, and focus promised by a cup of coffee.
Now that you know how it works – time for another cup?
Next time, I’ll discuss the long, varied, fascinating, and ultimately deeply-human story of how we co-evolved with this chemical, and the unexpected ways it’s changed the world we live in.
