TRPA1 Receptor Induced Relaxation of the Human Urethra Involves TRPV1 and Cannabinoid Receptor Mediated Signals, and Cyclooxygenase Activation
Author
Summary, in English
Purpose: We studied whether TRPA1 agonists interact with sensory and inflammatory signals to relax human urethral smooth muscle. Materials and Methods: Urethral specimens were obtained perioperatively from 19 patients, and prepared for immunohistochemistry and functional experiments. The effects of allyl isothiocyanate, cinnamaldehyde and NaHS were studied in phenylephrine activated preparations combined with capsaicin, capsazepine, N omega-nitro-L-arginine, indomethacin or CP55940. Results: TRPA1, cannabinoid 1 and cannabinoid 2 immunoreactivity was colocalized in nerve fibers of the human urethra. All TRPA1 agonists produced relaxation of phenylephrine contracted urethral preparations. Capsaicin increased relaxant responses to all TRPA1 agonists. It increased the mean SEM -logIC50 of cinnamaldehyde and NaHS from 4.91 +/- 0.26 to 5.15 +/- 0.22 and 3.27 +/- 0.14 to 3.79 +/- 0.35, and the -logIC30 of allyl isothiocyanate from 3.11 +/- 0.24 to 3.41 +/- 0.26 (each p < 0.05). Capsazepine in 5 preparations, indomethacin in 6 and CP55940 in 5 decreased cinnamaldehyde mediated relaxation by up to 39%, 88% and 89%, respectively. Nw-nitro-L-arginine and urothelial removal had no effect on relaxation by cinnamaldehyde in 5 preparations. Conclusions: Relaxation to TRPA1 agonists in human urethral preparations seem to work in cooperation with TRPV1 mediated signals, are negatively coupled via cannabinoid receptor activation and involve cyclooxygenase products. Urothelial TRPA1 signals may not be important to regulate normal human urethral smooth muscle tone. This does not exclude a role in the initiation of afferent activity normally and in disease states.
Department/s
Publishing year
2010
Language
English
Pages
2070-2076
Publication/Series
Journal of Urology
Volume
183
Issue
5
Document type
Journal article
Publisher
Lippincott Williams & Wilkins
Topic
- Urology and Nephrology
Keywords
- protein
- human
- TRPV1
- TRPA1 protein
- muscle relaxation
- urethra
- urothelium
Status
Published
ISBN/ISSN/Other
- ISSN: 1527-3792