ADORA2A
The ADORA2A gene encodes adenosine receptor activity which increases throughout the day as the body generates adenosine, a by-product of energy (ATP) release.
ADORA2A also regulates dopamine release - as adenosine levels increase, the stimulatory effect of dopamine declines - facilitating sleep. Caffeine blocks this interaction by increasing the stimulatory effect of dopamine, causing alertness.
Variants on ADORA2A increase the stimulatory impact of caffeine.
