Expression of different phosphodiesterase genes in human cavernous smooth muscle

Purpose: Knowledge of intracellular signal propagation in smooth muscle ton e regulation is of major importance in the understanding of the physiology of penile erection, and the development of new and selective pharmacologica l agents for the treatment of related disorders. Since phosphodiesterases ( PDE) are key enzymes of the signaling pathway, we elucidate their presence and potential functional relevance in human cavernous tissue. Materials and Methods: To identify PDE messenger RNA in human cavernous tis sue, we constructed primers for 14 published PDE isoforms. Expression of th e genes was then analyzed by reverse transcriptase polymerase chain reactio n under standard conditions and by subsequent sequencing. Results: Messenger RNA was detected in human corpus cavernosum for the huma n phosphodiesterase isoenzymes and isoforms PDE1A, PDE1B, PDE1C, PDE2A, PDE 3A, PDE4A, PDE4B, PDE4C, PDE4D, PDE5A, PDE7A, PDE8A and PDE9A. Conclusions: A total of 13 PDE genes were expressed in human cavernous tiss ue, indicating a role of these enzymes in penile erection regulation. The i ntracellular mechanisms of hydrolyzing cyclic adenosine monophosphate and c yclic guanosine monophosphate by PDEs are more complex than assumed previou sly. These findings open up new possibilities in the development of drugs f or the treatment of erectile dysfunction.