J Korean Androl Soc.  1994 Dec;12(2):109-117.

Mechanism of Action of Endothelium-Dependent Relaxation Substances on Rabbit Corpus Cavernosum

• Kim JJ
• Chung DY
• Koh SK

Abstract

Many relaxation substances cause endothelium-dependent vasodilation of various vessels. Relaxation of penile corpus cavernosum smooth muscle is controlled by nerves and a substance known as endothelium-derived relaxation factor(EDRF). The aim of this study was characterization of the mechanism of action of various relaxation substances on corpus cavernosum smooth muscle in the rabbit to determine whether these are endothelium dependent. Endothelium was removed by infusion of 3-[(3-cholamidopropyl)-dimethylammonio]-1-propan sulfonate(CHAPS), and removal was confirmed by acetylcholine-induced relaxation and immunocytochemical staining. Strips of rabbit corporal tissues were studied in an organ chamber for isometric tension measurement. The effects of acetylcholine, bethanechol, ATP, substance P, and bradykinin were measured in the presence or absence of endothelium and pretreatment with N-monomethyl-L-arginine(L-NMMA) and methylene blue(MB). Relaxation of corpus cavernosum tissue in response to acetycholine, ATP, substance P, and bradykinin was endothelium dependent; L-NMMA and MB did not have any effect on the relaxation of smooth muscle treated with ATP. Acetylcholine-, substance P-, and bradykinin-mediated endothelium-dependent relaxation of rabbit corpus cavernosum smooth mucle acts by the pathway of nitric oxide(NO) synthesis, whereas ATP-mediated endothelium-dependent relaxation does not. These results suggest that an EDRF pathway other than NO synthesis exists in endothelium-dependent relaxation.

MeSH Terms

Acetylcholine
Adenosine Triphosphate
Bethanechol
Bradykinin
Endothelium
Endothelium-Dependent Relaxing Factors
Male
Muscle, Smooth
Nitric Oxide
omega-N-Methylarginine
Penile Erection
Penis
Physiology
Relaxation*
Substance P
Vasodilation
Acetylcholine
Adenosine Triphosphate
Bethanechol
Bradykinin
Endothelium-Dependent Relaxing Factors
Nitric Oxide
Substance P
omega-N-Methylarginine