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cAMP ‐dependent post‐translational modification of neuronal nitric oxide synthase neuroprotects penile erection in rats
Author(s) -
Karakus Serkan,
Musicki Biljana,
La Favor Justin D.,
Burnett Arthur L.
Publication year - 2017
Publication title -
bju international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 1464-4096
DOI - 10.1111/bju.13981
Subject(s) - endocrinology , medicine , western blot , nitric oxide , penis , nitric oxide synthase , erectile dysfunction , chemistry , nerve injury , biochemistry , anesthesia , anatomy , gene
Objectives To evaluate neuronal nitric oxide ( NO ) synthase ( nNOS ) phosphorylation, nNOS uncoupling, and oxidative stress in the penis and major pelvic ganglia ( MPG ), before and after the administration of the cAMP ‐dependent protein kinase A ( PKA ) agonist colforsin in a rat model of bilateral cavernous nerve injury ( BCNI ),which mimics nerve injury after prostatectomy. Materials and Methods Adult male Sprague–Dawley rats were divided into BCNI and sham‐operated groups. Each group included two subgroups: vehicle and colforsin (0.1 mg/kg/day i.p.). After 3 days, erectile function (intracavernosal pressure) was measured and penis and MPG were collected for molecular analyses of phospho (P)‐ nNOS (Ser‐1412 and Ser‐847), total nNOS , nNOS uncoupling, binding of protein inhibitor of nNOS ( PIN ) to nNOS , gp91 phox subunit of NADPH oxidase, active caspase 3, PKA catalytic subunit α ( PKA ‐Cα; by Western blot) and oxidative stress (hydrogen peroxide [H 2 O 2 ] and superoxide by Western blot and microdialysis method). Results Erectile function was decreased 3 days after BCNI and normalized by colforsin. nNOS phosphorylation on both positive (Ser‐1412) and negative (Ser‐847) regulatory sites, and nNOS uncoupling, were increased after BCNI in the penis and MPG , and normalized by colforsin. H 2 O 2 and total reactive oxygen species production were increased in the penis after BCNI and normalized by colforsin. Protein expression of gp91 phox was increased in the MPG after BCNI and was normalized by colforsin treatment. Binding of PIN to nNOS was increased in the penis after BCNI and was normalized by colforsin treatment. Protein expression of active Caspase 3 was increased in the MPG after BCNI and was normalized by colforsin treatment. Protein expression of PKA ‐Cα was decreased in the penis after BCNI and normalized by colforsin. Conclusion Collectively, BCNI impairs nNOS function in the penis and MPG by mechanisms involving its phosphorylation and uncoupling in association with increased oxidative stress, resulting in erectile dysfunction. PKA activation by colforsin reverses these molecular changes and preserves penile erection in the face of BCNI .