ABSTRACT
The amplitude and duration of the cyclic nucleotide responses are determined by the balance between their rates of synthesis by adenylyl or guanylyl cyclases, and their rates of degradation by one or more cyclic nucleotide phosphodiesterases (PDEs). The difficulties concerning interpretation of selectivity are compounded when PDE inhibitors are used in intact cells or whole animals. As a result, the members of the PDE superfamily are well placed to be the targets for pharmacological interventions in a wide variety of pathological conditions impinging on these processes and in pathogenic organisms that inflict health and economic hardships. Signaling pathways employing adenosine 3',5' -cyclic monophosphate (cAMP) or guanosine 3',5' -monophosphate (cGMP) play a critical role in the control of myriad processes across a broad spectrum of organisms. The second messengers, cAMP and cGMP, were first identified by E. W. Sutherland and colleagues.
