RT info:eu-repo/semantics/article T1 Melatonin receptors MT1 and MT2 are expressed in spermatozoa from several seasonal and nonseasonal breeder species A1 González Arto, Marta A1 Vicente Carrillo, Alejandro A1 Martínez Pastor, Felipe A1 Fernández Alegre, Estela A1 Roca Aleu, Jorge A1 Miró Roig, Jordi A1 Rigau, Teresa A1 Rodríguez Gil, Joan Enric A1 Pérez Pé, Rosaura A1 Muiño Blanco, María Teresa A1 Cebrián Pérez, José A. A1 Casao Gascón, Adriana A2 Biologia Celular K1 Veterinaria K1 Donkey K1 Stallion K1 Boar K1 Bull K1 Deer K1 Dog AB Melatonin is a ubiquitous and multipurpose molecule, and one of its roles is to regulate reproduction in some seasonal mammals. Our group has previously reported the variation in the melatonin levels in ram seminal plasma along the year and identified MT1 and MT2 receptors in ram spermatozoa. The objective of this study was to elucidate whether the presence of melatonin receptors (MT1 and MT2) in the sperm plasma membrane, and melatonin in the seminal plasma is related to seasonal breeding. For this purpose, the presence of melatonin receptors and the levels of melatonin in seminal plasma have been examined in several species: donkey and stallion as long-day breeders; red deer as a wild, short-day, highly seasonal breeder (epididymal spermatozoa); bull as a conventional nonseasonal breeder; boar as a seasonal breeder under management techniques; and dog as possible a seasonal breeder not regulated by melatonin. We have detected measurable levels of melatonin in the seminal plasma of all ejaculated semen samples (from donkey, stallion, boar, bull, and dog). Also, and for the first time, we have demonstrated the presence of MT1 and MT2 melatonin receptors in the spermatozoa of all these species, regardless their type of reproduction or sperm source (ejaculated or epididymal), using indirect immunofluorescence techniques and Western blotting. Our findings suggest that melatonin and melatonin receptors may be universally distributed in the reproductive system of mammals and that the sperm melatonin receptors cells may not be necessarily related with seasonal reproduction. Furthermore, the presence of MT1 at the cytoplasmic droplet in immature ejaculated stallion spermatozoa found in one sample and epididymal red deer spermatozoa suggests that melatonin may be involved in specific functions during spermatogenesis and sperm maturation, like protecting spermatozoa from oxidative damage, this activity being mediated through these receptors. PB Elsevier YR 2019 FD 2019-05-17 LK http://hdl.handle.net/10612/10797 UL http://hdl.handle.net/10612/10797 NO Theriogenology, 2016, vol. 86, n. 8 NO P. 1958-1968 DS BULERIA. Repositorio Institucional de la Universidad de León RD 28-mar-2024