Vicente Carrillo, AlejandroÁlvarez Rodríguez, ManuelRodríguez Martínez, Heriberto2024-05-272024-05-272016-07-08Vicente-Carrillo, A., Álvarez-Rodríguez, M. and Rodríguez-Martínez, H. (2016), The mu (μ) and delta (δ) opioid receptors modulate boar sperm motility. Mol. Reprod. Dev., 83: 724-734. https://doi.org/10.1002/mrd.226751040-452X10.1002/mrd.22675https://hdl.handle.net/20.500.14352/104453Endogenous and exogenous opioids modulate reproductive functions in target cells via opioid receptors (μ, δ, and κ). Sperm motility is a metric of gamete functionality, and serves as a suitable parameter for in vitro drug-induced toxicity assays. This study identifies the presence and location of opioid receptors in pig spermatozoa as well as their functional response after in vitro challenge with known agonists (morphine [μ]; [D-Pen 2,5]-enkephanile [δ]; and U 50488 [κ]) and antagonists (naloxone [μ]; naltrindole [δ]; and nor-binaltrorphimine [κ]). Only the μ- and δ-opioid receptors were present in the boar sperm plasma membrane, overlying the acrosome, neck, and principal piece. Challenge experiments with agonists and antagonists identified both μ- and δ-opioid receptors as regulators of sperm kinematics, wherein μ maintains or increases sperm movement whereas δ decreases sperm motility over time.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/journal article1098-2795https://doi.org/10.1002/mrd.22675restricted access636.08Sperm motilityOpioid receptorCiencias BiomédicasVeterinariaProducción animal3104 Producción Animal24 Ciencias de la Vida3104.11 Reproducción