title: Naloxone increases maturation rate and ratio of inner cell mass to total cells in blastocysts in pigs.
abstract: The purposes of the present study were to examine the effect of naloxone, a mu-opioid receptor (MOR) antagonist, on porcine oocyte maturation and embryo development. MOR gene was expressed in germinal vesicle (GV) and metaphase II (M-II) porcine oocytes, one-, four-cell stage embryos and blastocysts. In blastocysts, MOR gene was mainly expressed in inner cell mass (ICM) cells. Supplementation of 10(-8) mol/L naloxone in in vitro maturation (IVM) medium increased the maturation rate (P < 0.05). However, 10(-4) mol/L naloxone reduced the maturation rate (P < 0.05) compared with the control. The presence of naloxone during IVM had no effects on fertilization status and subsequent embryonic development after in vitro culture (IVC). The addition of 10(-3) mol/L dibutyryl cyclic adenosine monophosphate (dbcAMP), and 10(-8 ) mol/L naloxone together into IVM medium increased nuclear maturation (P < 0.05) compared with the addition of either dbcAMP or naloxone alone. Supplementation with naloxone in IVC medium did not improve embryonic development. However, at the concentrations of 10(-6) mol/L and 10(-8) mol/L, naloxone increased the ratio of ICM to total cells in blastocysts (P < 0.05). In conclusion, at low concentration, naloxone increases maturation rate and the ratio of ICM to total cells in blastocysts. Naloxone and cAMP have a synergistic effect on oocyte maturation.
authors: Animal Breeding and Reproduction Division, NARO Institute of Livestock and Grassland; Graduate School of Life and Environmental Sciences, University of Tsukuba.
authors: Thanh Quang
authors: TQ
authors: Dang-Nguyen
authors: Nguyen
authors: N
authors: Viet Linh
authors: Rosa
authors: R
authors: Minoia
authors: Masahiro
authors: M
authors: Kaneda
authors: Tamas
authors: T
authors: Somfai
authors: Seiki
authors: S
authors: Haraguchi
authors: Satoshi
authors: S
authors: Akagi
authors: Kazuhiro
authors: K
authors: Kikuchi
authors: Michiko
authors: M
authors: Nakai
authors: Atsushi
authors: A
authors: Tajima
authors: Takashi
authors: T
authors: Nagai
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D047108:Embryonic Development / Q000187:drug effects* / Q000235:genetics; D005260:Female; D005307:Fertilization in Vitro; D066298:In Vitro Techniques; D009270:Naloxone / Q000494:pharmacology*; D009865:Oocytes / Q000166:cytology*; D009866:Oogenesis / Q000187:drug effects* / Q000235:genetics; D017450:Receptors, Opioid, mu / Q000037:antagonists & inhibitors* / Q000235:genetics; D013552:Swine
chemical_list: D017450:Receptors, Opioid, mu; D009270:Naloxone
keywords: in vitro culture; in vitro maturation; inner cell mass; mu-opioid receptor; naloxone