Participation of membrane adenylyl cyclase in heparin-induced capacitation in cryopreserved bovine spermatozoa

The aim of this work was to study the participation of membrane adenylyl cyclase in heparin-induced capacitation in cryopreserved bovine spermatozoa. Sperm suspensions were incubated in Tyrode´s albumin lactate pyruvate medium in the presence of heparin (10 IU ml(-1) ) or forskolin (1-75 μm), a well-known membrane adenylyl cyclase activator. The participation of membrane adenylyl cyclase was confirmed using a specific inhibitor, 2´,5´-dideoxyadenosine (6-25 μm). Spermatozoa capacitated with forskolin (25 μm) were incubated with bovine follicular fluid to evaluate their ability to undergo acrosome reaction. Capacitation percentages were determined by the fluorescence technique with chlortetracycline, and true acrosome reaction was determined by trypan blue and differential interferential contrast. The forskolin concentrations employed had no effect on progressive motility or sperm viability. Capacitation values induced by 25-μm forskolin treatment (27.80 ± 2.59%) were significantly higher respect to the control (4.80 ± 1.30%). The inhibitor 2´,5´-dideoxyadenosine prevented forskolin-induced capacitation and significantly diminished capacitation induced by heparin. Follicular fluid induced physiological acrosome reaction in spermatozoa previously capacitated with 25-μm forskolin (P < 0.05). Forskolin acts as a capacitation inducer and involves the participation of membrane adenylyl cyclase as part of the intracellular mechanisms that lead to capacitation in cryopreserved bovine spermatozoa.Fil: Breininger, Elizabeth. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Instituto de Investigacion y Tecnología en Reproducción Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Produccion Animal; ArgentinaFil: Ricart, María Cecilia. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Instituto de Investigacion y Tecnología en Reproducción Animal; ArgentinaFil: Beconi, Martha. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Instituto de Investigacion y Tecnología en Reproducción Animal; ArgentinaFil: Rodriguez, Pablo Cristian. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Instituto de Investigacion y Tecnología en Reproducción Animal; Argentin