title: Ethanol-induced extracellular signal regulated kinase: role of dopamine D1 receptors.
abstract: BACKGROUND
  Addictive drugs activate extracellular signal regulated kinase (ERK) in brain regions critically involved in their affective and motivational properties. The aim of this study was to demonstrate the ethanol-induced activation of ERK in the nucleus accumbens (Acb) and in the extended amygdala [bed nucleus of the stria terminalis lateralis (BSTL) and central nucleus of the amygdala (CeA)] and to highlight the role of dopamine (DA) D(1) receptors in these effects.
  
  
  METHODS
  Ethanol (0.5, 1, and 2 g/kg) was administered by gavage and ERK phosphorylation was determined in the nucleus Acb (shell and core), BSTL, and CeA by immunohistochemistry. The DA D(1) receptor antagonist, SCH 39166 (SCH) (50 microg/kg), was administered 10 minutes before ethanol (1 g/kg).
  
  
  RESULTS
  Quantitative microscopic examination showed that ethanol, dose-dependently increased phospho-ERK immunoreactivity (optical and neuronal densities) in the shell and core of nucleus Acb, BSTL, and CeA. Pretreatment with SCH fully prevented the increases elicited by ethanol (1 g/kg) in all brain regions studied.
  
  
  CONCLUSIONS
  The results of this study indicate that ethanol, similar to other addictive drugs, activates ERK in nucleus Acb and extended amygdala via a DA D(1) receptor-mediated mechanism. Overall, these results suggest that the D(1) receptors/ERK pathway may play a critical role in the motivational properties of ethanol.
authors.affiliation: Department of Toxicology, INN-National Institute of Neuroscience, University of Cagliari, Via Ospedale 72, Cagliari, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Ibba
authors.forename: Stefania
authors.initials: S
authors.lastname: Vinci
authors.forename: Saturnino
authors.initials: S
authors.lastname: Spiga
authors.forename: Alessandra T
authors.initials: AT
authors.lastname: Peana
authors.forename: Anna R
authors.initials: AR
authors.lastname: Assaretti
authors.forename: Liliana
authors.initials: L
authors.lastname: Spina
authors.forename: Rosanna
authors.initials: R
authors.lastname: Longoni
authors.forename: Elio
authors.initials: E
authors.lastname: Acquas