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Tadalafil attenuates hypotonicity‐induced Ca 2+ influx via TRPV2 and TRPV4 in primary rat bladder urothelial cell cultures
Author(s) -
Dong Xiao,
Nakagomi Hiroshi,
Miyamoto Tatsuya,
Ihara Tatsuya,
Kira Satoru,
Sawada Norifumi,
Mitsui Takahiko,
Takeda Masayuki
Publication year - 2018
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.23423
Subject(s) - urothelium , tadalafil , agonist , transient receptor potential channel , pharmacology , western blot , medicine , chemistry , microbiology and biotechnology , endocrinology , receptor , urinary bladder , biochemistry , biology , erectile dysfunction , gene
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. Ca 2+ 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. Ca 2+ influx induced by hypotonic stimulation, GSK1016790A, or cannabidiol was significantly inhibited by tadalafil, whereas ATP‐induced Ca 2+ 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 Ca 2+ 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.