Comment Re:Caffeine is a drug.. (Score 2) 212
More specifically, the chemical is a modified version of adenosine called cyclic AMP (cAMP). cAMP is generated by enzymes from ATP, the energy molecule of cells. It acts as a signal amplifier in cellular signaling cascades, and for the purposes of how caffeine affects the body, increased cAMP concentrations = more cellular metabolism. Think the adrenaline response at the cellular level.
Caffeine inhibits enzymes which break down cAMP and turn off the signal. No off switch = artificial build-up of cAMP in the cell = artificial high metabolism state.
Cocaine acts in a somewhat analogous manner, in that it doesn't increase the amount of neurotransmitters being released directly or directly stimulate neurons, but prevents released dopamine from being broken down and thus prolongs the signals artificially, leading to the psychological effects of cocaine use.