Cyclic Adenosine Monophosphate
important in the regulation of metabolic and neurologic processes and activity, cAMP is generated in response to the activation of cellular receptors and, in turn, the presence of cAMP within the cell activates the process in question. cAMP is broken down by cAMP-phosphodiesterase. The activity and duration of the process is governed by the rate at which cAMP is produced in response to receptor activation and the rate at which it is broken down. This is why the combination of ephedrine and caffeine produce a greater metabolic response than the sum of their effects when taken individually: ephedrine increseases receptor activation, caffiene inhibits cAMP breakdown.