European urology supplements vol:5 issue:14 pages:804-804
INTRODUCTION & OBJECTIVES: The vanilloid family of transient receptor potential channels (TRPV) is emerging as a promising group of medicinal targets. In bladder, one member of the TRPV family has already been studied extensively: vanilloid receptor subtype 1 (TRPV1). TRPV1 is known to occur on urothelium, nerve endings and on suburothelial and intermuscular interstitial cells (IC). Recently TRPV4, a new subtype of the TRPV family, has been described . In the present study we looked for the presence and topography of TRPV4 in bladder from mouse and rat.
MATERIAL & METHODS: Appropriate ethical approval was obtained. TRPV4−/− mice were generated as described by others . Polyclonal anti-TRPV4 antibodies were raised in rabbit. Immunohistochemistry was performed on 4 mm bladder
slides from mouse (TRPV4+/+ and TRPV4−/−) and rat (Wistar), using the threestep immunoperoxidase method. Immunofluorescence studies were performed using
confocal laserscanning microscopy on 20 mm bladder slides. Controls consisted of omission of primary antibodies.
RESULTS: Both immunohistochemistry (A) and immunofluorescence (B) showed TRPV4 immunoreactivity on urothelium and endothelium in both mouse and rat bladders, but not on any other cell type. No staining was found on urothelium and endothelium from TRPV4−/− bladders, which confirmed the specificity of the antibody.
Double staining with TRPV1 showed colocalisation on urothelium of both antigens.
CONCLUSIONS: In the present study we demonstrated for the first time the presence of TRPV4 in mouse and rat bladder. TRPV4 was found on urothelium and endothelium.
Further functional studies are indicated to elucidate the physiological role of this new receptor in bladder.