title: The presence and function of dopamine type 2 receptors in boar sperm: a possible role for dopamine in viability, capacitation, and modulation of sperm motility.
abstract: Several studies have shown that dopamine and other catecholamines are present in oviduct luminal fluid. We recently reported that dopamine type 2 receptors (DRD2) are present in a wide range of mammalian sperm, suggesting a role for dopaminergic signaling in events such as fertilization, capacitation, and sperm motility. In the present study, we used Western blot analysis to show that boar sperm express DRD2 and that their activation with dopamine (100 nM) has a positive effect on cell viability that can be correlated with AKT/PKB phosphorylation. Bromocriptine (100 nM) and dopamine (100 nM and 10 muM) increased tyrosine phosphorylation during the capacitation period. Immunofluorescence analysis indicated that DRD2 localization is dynamic and depends on the capacitation stage, colocalizing with tyrosine phosphorylated proteins in the acrosome and midpiece region of capacitated boar sperm. This association was confirmed by coimmunoprecipitation analysis. We also showed that bromocriptine (100 nM) and low-concentration dopamine (100 nM and 10 muM) increased total and progressive motility of sperm. However, high concentrations of dopamine (1 mM) decreased tyrosine phosphorylation and motility in in vitro sperm capacitation assays. This can be explained by the presence of the dopamine transporters (DAT, official symbol SLC6A3) in sperm, as demonstrated by Western blot analysis and immunocytochemistry. Taken together, our results support the idea that dopamine may have a fundamental role during sperm capacitation and motility in situ in the female upper reproductive tract.
authors.affiliation: Instituto de Bioquímica, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: Alfredo R
authors.initials: AR
authors.lastname: Ramírez
authors.forename: Maite A
authors.initials: MA
authors.lastname: Castro
authors.forename: Constanza
authors.initials: C
authors.lastname: Angulo
authors.forename: Laura
authors.initials: L
authors.lastname: Ramió
authors.forename: M Montserrat
authors.initials: MM
authors.lastname: Rivera
authors.forename: Mauricio
authors.initials: M
authors.lastname: Torres
authors.forename: Teresa
authors.initials: T
authors.lastname: Rigau
authors.forename: Joan E
authors.initials: JE
authors.lastname: Rodríguez-Gil
authors.forename: Ilona I
authors.initials: II
authors.lastname: Concha
mesh_terms: D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology; D002470:Cell Survival; D004298:Dopamine / Q000502:physiology*; D018491:Dopamine Agonists / Q000494:pharmacology; D008297:Male; D051058:Oncogene Protein v-akt / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000378:metabolism / Q000502:physiology*; D013075:Sperm Capacitation / Q000502:physiology*; D013081:Sperm Motility / Q000502:physiology*; D013094:Spermatozoa / Q000378:metabolism / Q000502:physiology; D034421:Sus scrofa / Q000378:metabolism / Q000502:physiology*; D014018:Tissue Distribution; D014443:Tyrosine / Q000378:metabolism
chemical_list: D018491:Dopamine Agonists; D017448:Receptors, Dopamine D2; D001971:Bromocriptine; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D051058:Oncogene Protein v-akt; D004298:Dopamine