LAUSR

AbstractcGMP-independent nitric oxide (NO) signaling occurs via S-nitrosylation. We evaluated whether aberrant S-nitrosylation operates in the penis under conditions of cavernous nerve injury and targets proteins involved in regulating erectile function. Adult male Sprague–Dawley rats underwent bilateral cavernous nerve crush injury (BCNI) or sham surgery. Rats were given a denitrosylation agent N-acetylcysteine (NAC, 300 mg/kg/day) or vehicle in drinking water starting 2 days before BCNI and continuing for 2 weeks following surgery. After assessment of erectile function (intracavernous pressure), penes were collected for measurements of S-nitrosylation by Saville–Griess and TMT-switch assays and PKG-I function by immunoblotting of phospho (P)-VASP-Ser-239. Erectile function was decreased (P < 0.05) after BCNI, and it was preserved (P < 0.05) by NAC treatment. Total S-nitrosothiols and total S-nitrosylated proteins were increased (P < 0.05) after BCNI, and these were partially prevented by NAC treatment. S-nitrosylation of sGC was increased (P < 0.05) after BCNI, and it was prevented (P < 0.05) by NAC treatment. S-nitrosylation of eNOS was increased (P < 0.05) after BCNI, and showed a trend towards decrease by NAC treatment. Protein expression of P-VASP-Ser-239 was decreased (P < 0.05) after BCNI, and showed a trend towards increase by NAC treatment. In conclusion, erectile dysfunction following BCNI is mediated in part by S-nitrosylation of eNOS and its downstream signaling mediator GC, while denitrosylation protects erectile function by preserving the NO/cGMP signaling pathway.