title: Sex differences in the effects of adolescent social deprivation on alcohol consumption in μ-opioid receptor knockout mice.
abstract: BACKGROUND
  Evidence based on clinical and experimental animal studies indicates that adolescent social deprivation influences alcohol consumption in a sex-dependent manner, perhaps by influencing stress responses. However, the mechanisms underlying the interaction between these phenomena remain to be elucidated. Since the μ-opioid receptor (MOP) has been reported to have key roles in social stress responses as well as the reinforcing/addictive effects of ethanol, MOP is a candidate molecule that may link adolescent social deprivation and subsequent alterations in alcohol consumption.
  
  
  OBJECTIVE
  To evaluate the involvement of MOP and social isolation-induced changes in alcohol consumption, as well as the effect of sex differences on responses to social isolation, alcohol consumption was assessed using a two-bottle home-cage consumption procedure (8 % ethanol vs. water) in MOP knockout (MOP-KO) and wild type (WT) mice of both sexes exposed to adolescent social deprivation or reared socially.
  
  
  RESULTS
  Isolation rearing had no effects upon alcohol consumption of WT mice, whereas it significantly altered alcohol consumption in both male and female MOP-KO mice. Interestingly, social isolation affected ethanol consumption differently in male and female mice. Ethanol consumption was increased in male MOP-KO mice, but decreased in female MOP-KO mice, by isolation rearing.
  
  
  CONCLUSIONS
  These results indicate that disturbances of MOP function influence the effects of isolation rearing on ethanol consumption in a sex-dependent manner. Consequently, this suggests the possibility that genetic variation that influences MOP function may have differential roles in alcoholism in men and women, and alcoholism treatments that target MOP function may be differentially effective in males and females.
authors.affiliation: Department of Biological Psychiatry, Tohoku University, Sendai, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Moriya
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kasahara
authors.forename: F Scott
authors.initials: FS
authors.lastname: Hall
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Sakakibara
authors.forename: George R
authors.initials: GR
authors.lastname: Uhl
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tomita
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sora
mesh_terms: D000367:Age Factors; D000428:Alcohol Drinking / Q000235:genetics* / Q000378:metabolism* / Q000523:psychology; D000818:Animals; D000431:Ethanol / Q000008:administration & dosage; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017450:Receptors, Opioid, mu / Q000172:deficiency* / Q000235:genetics*; D012727:Sex Characteristics; D012934:Social Isolation / Q000523:psychology; D013315:Stress, Psychological / Q000235:genetics / Q000378:metabolism / Q000523:psychology
chemical_list: D017450:Receptors, Opioid, mu; D000431:Ethanol