Tadalafil attenuates hypotonicity-induced Ca2+ influx via TRPV2 and TRPV4 in primary rat bladder urothelial cell cultures.
Neurourol Urodyn. 2018 Mar 22;:
Authors: Dong X, Nakagomi H, Miyamoto T, Ihara T, Kira S, Sawada N, Mitsui T, Takeda M
AIMS: To investigate the localization of phosphodiesterase 5 (PDE5) and the molecular mechanism underlying the effect of the PDE5 inhibitor tadalafil in signal transduction in the bladder urothelium.
METHODS: PDE5 expression in rat bladder tissues and cultured primary rat bladder urothelial cells was evaluated using immunochemistry and western blot assays. Ca2+ influx in cells exposed to isotonic solution, hypotonic solution, a selective transient receptor potential vanilloid 2 (TRPV2) channel agonist (cannabidiol), a selective TRPV4 channel agonist (GSK1016790A), a TRP cation channel melastatin 7 (TRPM7) channel agonist (PIP2), or a purinergic receptor agonist (ATP) in the presence or absence of 10 µM tadalafil was evaluated using calcium imaging techniques. We also evaluated stretch-induced changes in ATP concentration in the mouse bladder in the presence or absence of 100 µM tadalafil.
RESULTS: Immunochemistry and western blot analyses demonstrated that PDE5 is abundantly expressed in the bladder urothelium and in primary rat urothelial cells. Ca2+ influx induced by hypotonic stimulation, GSK1016790A, or cannabidiol was significantly inhibited by tadalafil, whereas ATP-induced Ca2+ influx was unaffected by tadalafil. PIP2 did not induce Ca2+ influx. ATP release in tadalafil-pretreated bladders significantly decreased compared to control bladders.
CONCLUSIONS: Tadalafil attenuates Ca2+ influx via TRPV4 and TRPV2, and inhibits ATP release in the bladder urothelium. These findings indicate that tadalafil functions as an inhibitor of urothelial signal transduction.
PMID: 29566267 [PubMed – as supplied by publisher]
Source: Estudios sobre Cannabidiol (CBD)