Lori Birder led the review process.
Original Basic Science Article
Article first published online: 28 OCT 2011
Copyright © 2011 Wiley Periodicals, Inc.
Neurourology and Urodynamics
Volume 31, Issue 1, pages 148–155, January 2012
How to Cite
Aizawa, N., Wyndaele, J.-J., Homma, Y. and Igawa, Y. (2012), Effects of TRPV4 cation channel activation on the primary bladder afferent activities of the rat. Neurourol. Urodyn., 31: 148–155. doi: 10.1002/nau.21212
Conflict of interest: none.
- Issue published online: 23 JAN 2012
- Article first published online: 28 OCT 2011
- Manuscript Accepted: 29 JUL 2011
- Manuscript Received: 13 JUN 2011
- Ministry of Education, Culture, Sport, Science and Technology of the Japanese Government. Grant Numbers: 40159588, 80595257
- afferent nerves;
- transient receptor potential (TRP);
- urinary bladder
Transient receptor potential vanilloid 4 (TRPV4) may affect afferent pathways innervating the bladder. We investigated the effects of GSK1016790A (GSK) and RN1734, a TRPV4 agonist and antagonist, respectively, and P2X-purinoceptor antagonists (TNP-ATP and PPADS) on cystometry (CMG), and the effect of GSK on single afferent fiber activities (SAAs) of the rat bladder and its relationship with capsaicin (Cap)-sensitivity.
Conscious female Sprague–Dawley rats were used for CMG measurements. In SAA measurements, under urethane anesthesia, SAA was identified by electrical stimulation of the pelvic nerve and by bladder distention. Cystometric parameters were measured before and after intravesical drug instillation. In SAA measurements, response with saline instillation served as baseline. Then, GSK was instilled three times, and finally Cap was instilled to investigate the relationship with Cap-sensitivity.
Intravesical GSK-instillation transiently decreased bladder capacity and voided volume, which were counteracted by RN1734, TNP-ATP, and PPADS. In SAA measurements, Aδ-fibers (n = 7) were not affected by either GSK or Cap. Based on the Cap-sensitivity, C-fibers could be divided into two subtypes: Cap-insensitive (n = 14) and Cap-sensitive (n = 8). In the Cap-insensitive C-fibers, GSK significantly increased the SAAs during the first instillation, but the increase attenuated with time, whereas GSK did not significantly affect the Cap-sensitive C-fibers.
The present results suggest that activation of TRPV4 in the bladder, probably urothelium, facilitates the micturition reflex by activation of the mechanosensitive, Cap-insensitive C-fibers of the primary bladder afferents in rats. Neurourol. Urodynam. 31:148–155, 2012. © 2011 Wiley Periodicals, Inc.