| Literature DB >> 19255435 |
Roberta d'Emmanuele di Villa Bianca1, Raffaella Sorrentino, Pasquale Maffia, Vincenzo Mirone, Ciro Imbimbo, Ferdinando Fusco, Raffaele De Palma, Louis J Ignarro, Giuseppe Cirino.
Abstract
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.Entities:
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Year: 2009 PMID： 19255435 PMCID： PMC2657379 DOI： 10.1073/pnas.0807974105
Source DB: PubMed Journal: Proc Natl Acad Sci U S A ISSN： 0027-8424 Impact factor: 11.205