What is the mechanism of action of caffeine?

Caffeine primarily exerts its effects as an adenosine antagonist. By blocking adenosine receptors in the brain, caffeine prevents the sedative effects normally mediated by adenosine, which is a neurotransmitter that promotes sleep and relaxation. This blockade leads to increased neuronal excitability, enhanced release of excitatory neurotransmitters, and ultimately results in increased alertness and wakefulness.

The mechanism of caffeine's action is particularly evident through its effects on the central nervous system, where it counters drowsiness and improves focus. It is also worth noting that the antagonism of adenosine receptors can lead to secondary effects on other neurotransmitter systems, such as increased dopamine signaling, contributing to the overall stimulating effects of caffeine.

Understanding caffeine's role as an adenosine antagonist is crucial for appreciating its widespread use and effects on mood, cognition, and physical performance.