What Receptors Does Caffeine Stimulate?

What Receptors Does Caffeine Stimulate? Caffeine, the most widely consumed psychoactive substance in the world, is used to promote wakefulness and enhance alertness. Like other wake-promoting drugs (stimulants and modafinil), caffeine enhances dopamine (DA) signaling in the brain, which it does predominantly by antagonizing adenosine A2A receptors (A2AR). Does caffeine stimulate the parasympathetic nervous system?