title: Social isolation rearing increases nucleus accumbens dopamine and norepinephrine responses to acute ethanol in adulthood.
abstract: BACKGROUND
  Early-life stress is associated with increased vulnerability to alcohol addiction. However, the neural substrates linking chronic childhood/adolescent stress and increased risk of alcohol addiction are not well understood. In the nucleus accumbens (NAc), dopamine (DA) and norepinephrine (NE) signaling can be profoundly influenced by stress, anxiety, and drugs of abuse, including ethanol (EtOH). Here, we employed a rodent model of early-life stress that results in enduring increases in behavioral risk factors of alcoholism to gain a better understanding of how chronic adolescent stress may impact the EtOH sensitivity of DA and NE release in the NAc.
  
  
  METHODS
  Male Long-Evans rats were either group housed (GH; 4 rats/cage) or socially isolated (SI; 1 rat/cage) for 6 weeks beginning on postnatal day 28. SI and GH rats were tested in adulthood for anxiety-like behaviors (elevated plus maze), and the effects of EtOH (1 and 2 g/kg; intraperitoneally.) on NAc DA and NE were assessed by microdialysis.
  
  
  RESULTS
  SI animals showed increased anxiety-like behavior compared to GH animals. Although SI had no effect on baseline levels of DA or NE, baseline DA levels were positively correlated with anxiety measures. In addition, while no significant differences were observed with 1 g/kg EtOH, the 2 g/kg dose induced significantly greater DA release in SI animals. Moreover, EtOH (2 g/kg) only elevated NAc NE levels in SI rats.
  
  
  CONCLUSIONS
  These results suggest that chronic early-life stress sensitizes accumbal DA and NE release in response to an acute EtOH challenge. A greater EtOH sensitivity of DA and NE release dynamics in the NAc may contribute to increases in behavioral risk factors of alcoholism, like greater EtOH self-administration, that are observed in SI rats.
authors.affiliation: Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina; Translational Center for the Neurobehavioral Study of Alcohol, Wake Forest School of Medicine, Winston-Salem, North Carolina.
authors.forename: Anushree N
authors.initials: AN
authors.lastname: Karkhanis
authors.forename: Jason L
authors.initials: JL
authors.lastname: Locke
authors.forename: Brian A
authors.initials: BA
authors.lastname: McCool
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Weiner
authors.forename: Sara R
authors.initials: SR
authors.lastname: Jones
mesh_terms: D000428:Alcohol Drinking / Q000378:metabolism* / Q000523:psychology; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D000431:Ethanol / Q000008:administration & dosage*; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D020318:Rats, Long-Evans; D012646:Self Administration; D012934:Social Isolation / Q000523:psychology
chemical_list: D000431:Ethanol; D004298:Dopamine; D009638:Norepinephrine
keywords: Dopamine; Ethanol; Norepinephrine; Nucleus Accumbens; Social Isolation