Hydrogen sulfide as a mediator of human corpus cavernosum smooth-muscle relaxation

作者：Roberta d’Emmanuele di Villa Bianca, Raffaella Sorrentino, Pasquale Maffia, Vincenzo G. Mirone, Ciro Imbimbo, Ferdinando Fusco, Raffaele De Palma, Louis Joseph Ignarro, Giuseppe Cirino · 发表于：Proceedings of the National Academy of Sciences · 年份：2009 · DOI：10.1073/pnas.0807974105 · 被引用次数：199 · 研究领域：Sexual function and dysfunction studies、Urinary Bladder and Prostate Research、Hormonal and reproductive studies

Hydrogen sulfide (H(2)S) is synthesized by 2 enzymes, cystathionine beta-synthase (CBS) and cystathionine gamma-lyase (CSE). L-Cysteine (L-Cys) acts as a natural substrate for the synthesis of H(2)S. Human penile tissue possesses both CBS and CSE, and tissue homogenates efficiently convert L-Cys to H(2)S. CBS and CSE are localized in the muscular trabeculae and the smooth-muscle component of the penile artery, whereas CSE but not CBS is also expressed in peripheral nerves. Exogenous H(2)S [sodium hydrogen sulfide (NaHS)] or L-Cys causes a concentration-dependent relaxation of strips of human corpus cavernosum. L-Cys relaxation is inhibited by the CBS inhibitor, aminoxyacetic acid (AOAA). Electrical field stimulation of human penile tissue, under resting conditions, causes an increase in tension that is significantly potentiated by either propargylglycine (PAG; CSE inhibitor) or AOAA. In rats, NaHS and L-Cys promote penile erection, and the response to L-Cys is blocked by PAG. Our data demonstrate that the L-Cys/H(2)S pathway mediates human corpus cavernosum smooth-muscle relaxation.