Abstract
Relaxation of the smooth muscle cells in the cavernosal arterioles and sinuses results in increased blood flow into the penis, raising corpus cavernosum pressure to culminate in penile erection1. Nitric oxide, released from non-adrenergic/non-cholinergic nerves, is considered the principle stimulator of cavernosal smooth muscle relaxation2,3,4, however, the inhibition of vasoconstrictors (that is, norepinephrine and endothelin-1, refs. 5–9) cannot be ignored as a potential regulator of penile erection. The calcium-sensitizing ρ-A/Rho-kinase pathway may play a synergistic role in cavernosal vasoconstriction to maintain penile flaccidity. Rho-kinase is known to inhibit myosin light chain phosphatase10,11,12, and to directly phosphorylate myosin light-chain (in solution), altogether resulting in a net increase in activated myosin and the promotion of cellular contraction10,11,13,14,15,16. Although Rho-kinase protein and mRNA have been detected in cavernosal tissue17, the role of Rho-kinase in the regulation of cavernosal tone is unknown. Using pharmacologic antagonism (Y-27632, ref. 13, 18), we examined the role of Rho-kinase in cavernosal tone, based on the hypothesis that antagonism of Rho-kinase results in increased corpus cavernosum pressure, initiating the erectile response independently of nitric oxide. Our finding, that Rho-kinase antagonism stimulates rat penile erection independently of nitric oxide, introduces a potential alternate avenue for the treatment of erectile dysfunction.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Caspase-3 dependent nitrergic neuronal apoptosis following cavernous nerve injury is mediated via RhoA and ROCK activation in major pelvic ganglion
Scientific Reports Open Access 08 July 2016
Access options
Subscribe to this journal
Receive 12 print issues and online access
$189.00 per year
only $15.75 per issue
Rent or buy this article
Get just this article for as long as you need it
$39.95
Prices may be subject to local taxes which are calculated during checkout



References
Andersson, K.E. & Stief, C. G. Neurotransmission and the contraction and relaxation of penile erectile tissues. World J. Urol. 15, 14–20 (1997).
Burnett, A.L. Neurophysiology of Erectile Function and Dysfunction. in The Handbook of Sexual Dysfunction (ed., Hellstrom, W.J.) 12–17 (The American Society of Andrology, California, 1999).
Escrig, A., Gonzalez-Mora, J.L. & Mas, M. Nitric oxide release in penile corpora cavernosa in a rat model of erection. J. Physiol. 516, 261–269 (1999).
Rosselli, M. Keller, P.J. & Dubey, R.K. Role of nitric oxide in the biology, physiology and pathophysiology of reproduction. Hum. Repro. Update 4, 3–24 (1998).
Cellek, S. Nitrergic-noradrenergic interaction in penile erection: A new insight into erectile dysfunction. Drugs of Today 36, 135–146 (2000).
Cellek, S. & Moncada, S. Nitrenergic control of peripheral sympathetic responses in the human corpus cavernosum: a comparison with other species. Proc. Natl. Acad. Sci. USA 94, 8226–8231 (1997).
Dai, Y et al. Receptor-specific influence of endothelin-1 in the erectile response of the rat. Am. J. Physiol. 279, R25–30 (2000).
Giraldi, A., Serels, S., Autieri, M., Melman, A. & Christ, G.J. Endothelin-1 as a putative modulator of gene expression and cellular physiology in cultured human corporal smooth muscle cells. J. Urol. 160, 1856–1862 (1998).
Ari, G., Vardi, Y., Hoffman, A. & Finberg, J.P. Possible role for endothelins in penile erection. Eur. J. Pharm. 307, 69–74 (1996).
Somlyo, A.P. & Somlyo, A.V. Signal transduction by G-proteins, ρ-kinase and protein phosphatase to smooth muscle and non-muscle myosin II. J. Physiol. 522, 177–185 (2000).
Somlyo, A.P. & Somlyo. A.V. From pharmacomechanical coupling to G-proteins and myosin phosphatase. Acta Physiol. Scand. 164, 437–448 (1998).
Kimura, K. et al. Regulation of myosin phosphatase by ρ- and ρ-associated-kinase (ρ-kinase). Science 273, 245–248 (1996).
Uehata, M. et al. Calcium sensitization of smooth muscle mediated by a ρ-associated protein kinase in hypertension. Nature 389, 990–994 (1997).
Amano, M. et al. Phosphorylation and activation of myosin by ρ-associated kinase (ρ-kinase). J. Biol. Chem. 271, 20246–20249 (1996).
Feng, J. et al. ρ-associated kinase of chicken gizzard smooth muscle. J. Biol. Chem. 274, 3744–3752 (1999).
Kureishi, Y. et al. ρ-associated kinase directly induces smooth muscle contraction through myosin light chain phosphorylation. J. Biol. Chem. 272, 12257–12260 (1997).
Chang, S., Hypoilte, J.A., Wein, A.J., Chacko, S. & DiSanto, M.E. Expression of myosin light-chain kinase and ρ-associated kinase in corpus cavernosum smooth muscle. Biophys J. 78, 139A (2000).
Ishizaki, T. et al. Pharmacological properties of Y-27632, a specific inhibitor of ρ-associated kinases. Mol. Pharmacol. 57, 976–983 (2000).
Reilly, C.M., Zamorano, P., Stopper, V.S. & Mills, T.M. Androgenic regulation of NO availability in rat penile erection. J. Androl. 18, 110–115 (1997).
Reilly, C.M., Lewis, R.W., Stopper, V.S, & Mills, T.M. Androgenic maintenance of the rat erectile response via a non-nitric-oxide-dependent pathway. J. Andrology. 18, 588–594 (1997).
Moody, J.A., Vernet, D., Laidlaw, S., Rajfer, J. & Gonzalez-Cadavid, N.F. Effects of long-term oral administration of L-arginine on the rat erectile response. J. Urol. 158, 942–947 (1997).
Weber, D.S. & Webb, R.C. Enhanced relaxation to the ρ-kinase inhibitor Y-27632 in mesenteric arteries from mineralocorticoid hypertensive rats. Pharmacology in press.
Virag, R. Indications and early results of sildenafil (Viagra) in erectile dysfunction. Urology 54, 1073–1077 (1999).
Jarow, J.P., Burnett, A.L. & Geringer, A.M. Clinical efficacy of sildenafil citrate based on etiology and response to prior treatment. J. Urol. 162, 722–725 (1999).
Lowry, O.H., Rosebrough, N.Y., Farr, A.L. & Randall, R.J. Protein measurement with the folin reagent. J. Biol. Chem. 193, 265–275 (1951).
Mills, T.M., Lewis, R.W. & Stopper, V.S. Androgenic maintenance of inflow and veno-occlusion during erection in the rat. Biol. Reprod. 59, 1413–1418 (1998).
Acknowledgements
This work was supported by grants from the National Institutes of Health (NIH HL18575), American Heart Association (AHA 9960075V, Southeast Affiliate), and American Health Assistance Foundation (AHAF H2000011). K.C. is the recipient of support from a NIH training grant for Systems and Integrative Physiology (2-T32-GM0832211). Y-27632 was a gift from Welfide Corporation. We thank A. Dorrance for her assistance with western-blot analysis.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Chitaley, K., Wingard, C., Clinton Webb, R. et al. Antagonism of Rho-kinase stimulates rat penile erection via a nitric oxide-independent pathway. Nat Med 7, 119–122 (2001). https://doi.org/10.1038/83258
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/83258
This article is cited by
-
Alleviation of impaired reactivity in the corpus cavernosum of STZ-diabetic rats by slow-release H2S donor GYY4137
International Journal of Impotence Research (2019)
-
The mechanisms and potential of stem cell therapy for penile fibrosis
Nature Reviews Urology (2019)
-
Erectile dysfunction
Nature Reviews Disease Primers (2016)
-
Erection rehabilitation following prostatectomy — current strategies and future directions
Nature Reviews Urology (2016)
-
Caspase-3 dependent nitrergic neuronal apoptosis following cavernous nerve injury is mediated via RhoA and ROCK activation in major pelvic ganglion
Scientific Reports (2016)