Many seven transmembrane (7TM) receptors exert their influence upon cellular processes through G-protein stimulated activation of adenylyl cyclase leading to an increase in intracellular concentration of the second messenger cAMP which exists ubiquitously in mammalian cells. The sole role of cAMP is to activate cAMP-dependent protein kinase by binding to its regulatory subunits thus causing their dissociation from and activation of the catalytic subunits. Modulation of cAMP levels has been implicated in a variety of metabolic processes as diverse as muscle contraction, neurotransmission, exocytosis, cell growth and differentiation and platelet aggregation. In addition, reductions in intracellular cAMP concentrations have been observed in a variety of disease states and conditions such as congestive heart failure, diabetes, and cancer as well as a number of inflammatory conditions including asthma, rheumatoid athritis and atopic dermatitis.