PURPOSE: The intracellular messenger cyclic guanosine monophosphate (cGMP) has an important role in regulating smooth muscle tone. An increase in intracellular cGMP levels is a prerequisite for penile erection. Inhibition of cGMP degradation by cGMP specific phosphodiesterase 5 has been used for treating erectile dysfunction. In addition to degradation by phosphodiesterase, cGMP is exported from cells by multidrug resistance protein 5 (MRP5), also called ABCC5, which we recently identified as an adenosine triphosphate dependent export pump for cGMP. MRP5 is potently inhibited by substances known as phosphodiesterase inhibitors, including sildenafil and trequinsin. Therefore, we analyzed whether MRP5 is expressed in tissues of the human genitourinary system and whether MRP5 and phosphodiesterase 5 proteins are localized in the same cell types. MATERIALS AND METHODS: Localization of MRP5 and phosphodiesterase 5 was analyzed by immunofluorescence microscopy in cryosections of various tissues of the human genitourinary system. RESULTS: MRP5 and phosphodiesterase 5 were co-expressed in smooth muscle cells of the corpus cavernosum, ureter, urethra and bladder. In addition, MRP5 and phosphodiesterase 5 were localized in epithelial cells of the mucosa in the ureter and urethra, and in blood vessels of the lamina propria. CONCLUSIONS: The co-expression of MRP5 and phosphodiesterase 5 in smooth muscle cells of the genitourinary system indicates 2 distinct pathways for cGMP removal. Thus, MRP5 inhibition represents a new approach for enhancing cGMP levels in smooth muscle cells and developing drugs for erectile dysfunction.
PURPOSE: The intracellular messenger cyclic guanosine monophosphate (cGMP) has an important role in regulating smooth muscle tone. An increase in intracellular cGMP levels is a prerequisite for penile erection. Inhibition of cGMP degradation by cGMP specific phosphodiesterase 5 has been used for treating erectile dysfunction. In addition to degradation by phosphodiesterase, cGMP is exported from cells by multidrug resistance protein 5 (MRP5), also called ABCC5, which we recently identified as an adenosine triphosphate dependent export pump for cGMP. MRP5 is potently inhibited by substances known as phosphodiesterase inhibitors, including sildenafil and trequinsin. Therefore, we analyzed whether MRP5 is expressed in tissues of the human genitourinary system and whether MRP5 and phosphodiesterase 5 proteins are localized in the same cell types. MATERIALS AND METHODS: Localization of MRP5 and phosphodiesterase 5 was analyzed by immunofluorescence microscopy in cryosections of various tissues of the human genitourinary system. RESULTS:MRP5 and phosphodiesterase 5 were co-expressed in smooth muscle cells of the corpus cavernosum, ureter, urethra and bladder. In addition, MRP5 and phosphodiesterase 5 were localized in epithelial cells of the mucosa in the ureter and urethra, and in blood vessels of the lamina propria. CONCLUSIONS: The co-expression of MRP5 and phosphodiesterase 5 in smooth muscle cells of the genitourinary system indicates 2 distinct pathways for cGMP removal. Thus, MRP5 inhibition represents a new approach for enhancing cGMP levels in smooth muscle cells and developing drugs for erectile dysfunction.
Authors: Henriette E U Meyer Zu Schwabedissen; Markus Grube; Björn Heydrich; Knud Linnemann; Christoph Fusch; Heyo K Kroemer; Gabriele Jedlitschky Journal: Am J Pathol Date: 2005-01 Impact factor: 4.307
Authors: Christian Gratzke; Stefan Uckert; Giorgi Kedia; Oliver Reich; Boris Schlenker; Michael Seitz; Armin J Becker; Christian G Stief Journal: Urol Res Date: 2006-11-11
Authors: Peter Dazert; Konrad Meissner; Silke Vogelgesang; Björn Heydrich; Lothar Eckel; Michael Böhm; Rolf Warzok; Reinhold Kerb; Ulrich Brinkmann; Elke Schaeffeler; Matthias Schwab; Ingolf Cascorbi; Gabriele Jedlitschky; Heyo K Kroemer Journal: Am J Pathol Date: 2003-10 Impact factor: 4.307