Re:To paraphrase Captain Kirk (Score 1)

Caffeine does what it does because it mimics and inhibits the effects of adenosine, a common neurotransmitter that itself acts as a CNS inhibitor, so it could be said that caffeine is an "inhibitor inhibitor". In humans, this has the pleasant effects that we've come to know and love. The nervous system of insects, however, employs adenosine somewhat differently, so the effects of caffeine are considerably more dramatic. Viva Wikipedia! http://en.wikipedia.org/wiki/Caffeine#Mechanism_of_action