title: Expression and Localization of Opioid Receptors in Male Germ Cells and the Implication for Mouse Spermatogenesis.
abstract: The presence of endogenous opioid peptides in different testicular cell types has been extensively characterized and provides evidence for the participation of the opioid system in the regulation of testicular function. However, the exact role of the opioid system during the spermatogenesis has remained controversial since the presence of the mu-, delta- and kappa-opioid receptors in spermatogenic cells was yet to be demonstrated. Through a combination of quantitative real-time PCR, immunofluorescence, immunohistochemistry and flow cytometry approaches, we report for the first time the presence of active mu-, delta- and kappa-opioid receptors in mouse male germ cells. They show an exposition time-dependent response to opioid agonist, hence suggesting their active involvement in spermatogenesis. Our results contribute to understanding the role of the opioid receptors in the spermatogenesis and could help to develop new strategies to employ the opioid system as a biochemical tool for the diagnosis and treatment of male infertility.
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Haizea
authors.initials: H
authors.lastname: Estomba
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Iraia
authors.initials: I
authors.lastname: Muñoa-Hoyos
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Gianzo
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Itziar
authors.initials: I
authors.lastname: Urizar-Arenaza
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Casis
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Jon
authors.initials: J
authors.lastname: Irazusta
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Nerea
authors.initials: N
authors.lastname: Subirán
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D008297:Male; D051379:Mice; D060888:Real-Time Polymerase Chain Reaction; D017465:Receptors, Opioid, delta / Q000819:agonists / Q000032:analysis* / Q000235:genetics; D017473:Receptors, Opioid, kappa / Q000819:agonists / Q000032:analysis* / Q000235:genetics; D017450:Receptors, Opioid, mu / Q000819:agonists / Q000032:analysis* / Q000235:genetics; D013091:Spermatogenesis / Q000187:drug effects; D013094:Spermatozoa / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013737:Testis / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
chemical_list: D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu