title: Nitric oxide induces acrosome reaction in cryopreserved bovine spermatozoa.
abstract: The aim of this work was to study the effect of nitric oxide on acrosome reaction (AR) and the participation of protein kinases and reactive oxygen species in the AR of cryopreserved bovine spermatozoa. Spermatozoa were capacitated in Tyrode's albumin lactate pyruvate medium with heparin (10 IU ml(-1)) and then incubated with different concentrations of sodium nitroprusside (SNP) (1-200 micromol l(-1)). Methylene blue and haemoglobin were used to confirm the role of nitric oxide as an inducer of the AR. The participation of protein kinase A (PKA) , protein kinase C (PKC) and protein tyrosine kinase was evaluated using specific inhibitors of these enzymes (H-89, 50 micromol l(-1); bisindolylmaleimide I, 0.1 micromol l(-1) and genistein, 3 micromol l(-1)). The role of hydrogen peroxide or superoxide anion was evaluated by incubation with catalase or superoxide dismutase respectively. AR percentages were determined by the fluorescence technique with chlortetracycline. The highest levels of AR were obtained in capacitated spermatozoa treated with 5-200 micromol l(-1) SNP (24.8 +/- 1.8%). The presence of PKA, PKC and protein tyrosine kinase inhibitors likewise decreased AR percentages. The addition of superoxide dismutase had no effect on the AR level but catalase completely blocked it. These results indicate that nitric oxide induces AR in capacitated spermatozoa involving hydrogen peroxide and the participation of PKA, PKC and protein tyrosine kinase as part of the signal transduction mechanism which lead to the AR in cryopreserved bovine spermatozoa.
authors.affiliation: Area of Biochemistry, School of Veterinary Sciences, University of Buenos Aires, Chorroarin 280, C1427CWO Buenos Aires, Argentina. prodriguez@fvet.uba.ar
authors.forename: P C
authors.initials: PC
authors.lastname: Rodriguez
authors.forename: C M
authors.initials: CM
authors.lastname: O'Flaherty
authors.forename: M T
authors.initials: MT
authors.lastname: Beconi
authors.forename: N B
authors.initials: NB
authors.lastname: Beorlegui
mesh_terms: D020101:Acrosome Reaction / Q000187:drug effects*; D000818:Animals; D002374:Catalase / Q000378:metabolism; D002417:Cattle; D015925:Cryopreservation; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D006454:Hemoglobins / Q000494:pharmacology; D008297:Male; D008751:Methylene Blue / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012662:Semen Preservation / Q000379:methods; D013094:Spermatozoa / Q000187:drug effects*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D006454:Hemoglobins; D047428:Protein Kinase Inhibitors; D017382:Reactive Oxygen Species; D009599:Nitroprusside; D009569:Nitric Oxide; D002374:Catalase; D013482:Superoxide Dismutase; D011505:Protein-Tyrosine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D008751:Methylene Blue