Understanding caffeine’s work inside our brains can be as easy as saying as “it keeps me awake”. However its specific mechanisms are far more interesting than that. In fact it will take a series of explanations before we get to the point of explaining why it does. So before you move on with this, drink one coffee up, then read on.

Caffeine is the most accessible psychoactive substance there is. Your kitchen shelves and storages will prove this. Coming from the word psychoactive, it activates the psychological aspect of the human body or more popularly called the human mind. The process begins from the fact that when caffeine is metabolized by the liver, it breaks down into three components.

These components are paraxanthine, theobromine and theophylline. Its effects are lypolysis (the breakdown of fatty acids), dilation of blood vessels which leads to an increase in urine production and relaxes smooth muscles of the bronchi of the lungs.

Paraxanthine in caffeine is specifically responsible for the heightened alertness and sleeplessness. One of its effects or roles is to be a nonselective adenosine receptor antagonist. This means that it opposes the functions of adenosine receptors, which is to bind with adenosine – the chemical responsible why people go to sleep. Caffeine is able to do this because:

1. It can pass from your bloodstream directly to your brain (that’s what it means when medically inclined people say it can pass through blood-brain barriers)

2. Its molecular structure is similar to adenosine. Instead of adenosine binding to adenosine receptors, caffeine has the ability to take its place.

Without caffeine interference, what normally happens is that once adenosine binds with adenosine receptors it slows down metabolic processes in the brain. It does this by reducing the action of synapses (sort of cute storage spaces at the end of each nerve) of releasing chemicals that are responsible for impulses to travel from all over your body to the brain and vice versa.

Having the activity of the chemicals reduced at a lower rate (courtesy of the binding of adenosine to the adenosine receptors) almost all of the activities of the human body will soon regress to a state of rest and then eventually to sleep.

Stop. Read the previous paragraph. Have you understood the role of adenosine and adenosine receptors in a person’s sleep cycle? If you did, then you must have come to a conclusion: that stopping the function of adenosine receptors is like canceling sleep itself.

Blocking its function prevents other chemicals (intended for the brain to consciously respond to impulses) from being released from the synapses, thus metabolism, activity, or normal brain processes remain untouched. That’s what paraxanthine does to your adenosine receptors. And since paraxanthine is a metabolized product from caffeine, logically that’s what caffeine does to your mind. It simply “keeps you awake.”