Eli5: If caffeine connects to the same receptors as adenosine, why does it have the opposite effect?

Question

I understand that it doesn’t allow adenosine to connect to the receptors, but if the receptor doesn’t know which molecule connected, it should unleash the same reaction, right?

In: Chemistry

Answer 1

In the simplest terms, Adenosine has a reaction with the receptor, caffeine does not have a reaction. Thus, it blocks adenosine from being effective.

It’s not that caffeine does the opposite, it just ‘plugs’ the hole and keeps adenosine from doing its job.