Alcohol stimulates the release of dopamine in the ventral pallidum but not in the globus pallidus: A dual-probemicrodialysis study

Roberto I. Melendez, Zachary A. Rodd-Henricks, William J. McBride, James M. Murphy

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

The mesoaccumbens dopamine system has been hypothesized to be a common neural substrate mediating the actions of various drugs of abuse, including ethanol. However, the involvement of the mesopallidal dopamine system has received very little attention. The present study examined the effects of intraperitoneal (IP) ethanol administration on the extracellular levels of dopamine in the ventral pallidum (VP) and globus pallidus (GP) of Wistar rats. Rats were bilaterally implanted with microdialysis probes aimed at the VP and GP or nucleus accumbens (NAc) and dorsal striatum (dSTR). During microdialysis testing, rats with probes located in the VP and GP were injected IP with sterile saline or 15% (v/v) ethanol in saline at doses of 0.75, 1.5, or 2.25 g/kg. Rats with NAc and dSTR probes were injected with saline or 2.25 g/kg ethanol. The IP administration of 1.5 and 2.25 g/kg ethanol significantly (p <0.05) elevated the extracellular levels of dopamine in the VP (maximal increase: 136 and 182% of baseline, respectively) but not in the GP. No effects on extracellular dopamine levels were observed following the IP injections of 0.75 g/kg ethanol or saline. The IP administration of 2.25 g/kg ethanol significantly (p <0.05) elevated the extracellular levels of dopamine in the NAc (maximal increase: 198% of baseline) and dSTR (maximal increase: 155% of baseline). Analysis of the effects of 2.25 g/kg ethanol on dopamine release revealed greater increases in the VP, NAc, and dSTR compared to the GP. The data suggest that the mesopallidal, mesoaccumbens, and nigrostriatal dopamine systems are more sensitive to the effects of ethanol than the nigropallidal dopamine system.

Original languageEnglish (US)
Pages (from-to)939-946
Number of pages8
JournalNeuropsychopharmacology
Volume28
Issue number5
DOIs
StatePublished - May 2003

Keywords

  • Ethanol
  • Globuspallidus
  • Mesopallidaldopamine system
  • Microdialysis
  • Ventralpallidum

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health

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