Chronic ethanol drinking by alcohol-preferring rats increases the sensitivity of the posterior ventral tegmental area to the reinforcing effects of ethanol

Zachary Rodd, Richard Bell, Victoria K. McQueen, Michelle R. Davids, Cathleen C. Hsu, James M. Murphy, Ting Kai Li, Lawrence Lumeng, William J. McBride

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Background: The ventral tegmental area (VTA) is involved in regulating ethanol drinking, and the posterior VTA seems to be a neuroanatomical substrate that mediates the reinforcing effects of ethanol in ethanol-naïve Wistar and ethanol-naive alcohol-preferring (P) rats. The objective of this study was to test the hypothesis that chronic ethanol drinking increases the sensitivity of the posterior VTA to the reinforcing effects of ethanol. Methods: Two groups of female P rats (one given water as its sole source of fluid and the other given 24-hr free-choice access to 15% ethanol and water for at least 8 weeks) were stereotaxically implanted with guide cannulae aimed at the posterior VTA. One week after surgery, rats were placed in standard two-lever (active and inactive) operant chambers and connected to the microinfusion system. Depression of the active lever produced the infusion of 100 nl of artificial cerebrospinal fluid (CSF) or ethanol. The ethanol-naïve and chronic ethanol-drinking groups were assigned to subgroups to receive artificial CSF or 25, 50, 75, or 125 mg/dl of ethanol (n = 6-9/dose/group) to self-infuse (FR1 schedule) during the 4-hr sessions given every other day. Results: Compared with the infusions of artificial CSF, the control group reliably (p < 0.05) self-infused 75 and 125 mg/dl of ethanol but not the lower concentrations. The ethanol-drinking group had significantly (p < 0.05) higher self-infusions of 50, 75, and 125 mg/dl of ethanol than artificial CSF during the four acquisition sessions; the number of infusions of all three doses was higher in the ethanol-drinking group than in the ethanol-naive group. Both groups decreased responding on the active lever when artificial CSF was substituted for ethanol, and both groups demonstrated robust reinstatement of responding on the active lever when ethanol was restored. Conclusions: Chronic ethanol drinking by P rats increased the sensitivity of the posterior VTA to the reinforcing effects of ethanol.

Original languageEnglish
Pages (from-to)358-366
Number of pages9
JournalAlcoholism: Clinical and Experimental Research
Volume29
Issue number3
DOIs
StatePublished - Mar 2005

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Ventral Tegmental Area
Alcohol Drinking
Rats
Ethanol
Alcohols
Cerebrospinal fluid
Drinking
Cerebrospinal Fluid

Keywords

  • Ethanol Reinforcement
  • Ethanol Reward
  • Intracranial Self-Administration
  • Neuroadaptations
  • Sensitization

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Toxicology

Cite this

Chronic ethanol drinking by alcohol-preferring rats increases the sensitivity of the posterior ventral tegmental area to the reinforcing effects of ethanol. / Rodd, Zachary; Bell, Richard; McQueen, Victoria K.; Davids, Michelle R.; Hsu, Cathleen C.; Murphy, James M.; Li, Ting Kai; Lumeng, Lawrence; McBride, William J.

In: Alcoholism: Clinical and Experimental Research, Vol. 29, No. 3, 03.2005, p. 358-366.

Research output: Contribution to journalArticle

Rodd, Zachary ; Bell, Richard ; McQueen, Victoria K. ; Davids, Michelle R. ; Hsu, Cathleen C. ; Murphy, James M. ; Li, Ting Kai ; Lumeng, Lawrence ; McBride, William J. / Chronic ethanol drinking by alcohol-preferring rats increases the sensitivity of the posterior ventral tegmental area to the reinforcing effects of ethanol. In: Alcoholism: Clinical and Experimental Research. 2005 ; Vol. 29, No. 3. pp. 358-366.
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abstract = "Background: The ventral tegmental area (VTA) is involved in regulating ethanol drinking, and the posterior VTA seems to be a neuroanatomical substrate that mediates the reinforcing effects of ethanol in ethanol-na{\"i}ve Wistar and ethanol-naive alcohol-preferring (P) rats. The objective of this study was to test the hypothesis that chronic ethanol drinking increases the sensitivity of the posterior VTA to the reinforcing effects of ethanol. Methods: Two groups of female P rats (one given water as its sole source of fluid and the other given 24-hr free-choice access to 15{\%} ethanol and water for at least 8 weeks) were stereotaxically implanted with guide cannulae aimed at the posterior VTA. One week after surgery, rats were placed in standard two-lever (active and inactive) operant chambers and connected to the microinfusion system. Depression of the active lever produced the infusion of 100 nl of artificial cerebrospinal fluid (CSF) or ethanol. The ethanol-na{\"i}ve and chronic ethanol-drinking groups were assigned to subgroups to receive artificial CSF or 25, 50, 75, or 125 mg/dl of ethanol (n = 6-9/dose/group) to self-infuse (FR1 schedule) during the 4-hr sessions given every other day. Results: Compared with the infusions of artificial CSF, the control group reliably (p < 0.05) self-infused 75 and 125 mg/dl of ethanol but not the lower concentrations. The ethanol-drinking group had significantly (p < 0.05) higher self-infusions of 50, 75, and 125 mg/dl of ethanol than artificial CSF during the four acquisition sessions; the number of infusions of all three doses was higher in the ethanol-drinking group than in the ethanol-naive group. Both groups decreased responding on the active lever when artificial CSF was substituted for ethanol, and both groups demonstrated robust reinstatement of responding on the active lever when ethanol was restored. Conclusions: Chronic ethanol drinking by P rats increased the sensitivity of the posterior VTA to the reinforcing effects of ethanol.",
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author = "Zachary Rodd and Richard Bell and McQueen, {Victoria K.} and Davids, {Michelle R.} and Hsu, {Cathleen C.} and Murphy, {James M.} and Li, {Ting Kai} and Lawrence Lumeng and McBride, {William J.}",
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T1 - Chronic ethanol drinking by alcohol-preferring rats increases the sensitivity of the posterior ventral tegmental area to the reinforcing effects of ethanol

AU - Rodd, Zachary

AU - Bell, Richard

AU - McQueen, Victoria K.

AU - Davids, Michelle R.

AU - Hsu, Cathleen C.

AU - Murphy, James M.

AU - Li, Ting Kai

AU - Lumeng, Lawrence

AU - McBride, William J.

PY - 2005/3

Y1 - 2005/3

N2 - Background: The ventral tegmental area (VTA) is involved in regulating ethanol drinking, and the posterior VTA seems to be a neuroanatomical substrate that mediates the reinforcing effects of ethanol in ethanol-naïve Wistar and ethanol-naive alcohol-preferring (P) rats. The objective of this study was to test the hypothesis that chronic ethanol drinking increases the sensitivity of the posterior VTA to the reinforcing effects of ethanol. Methods: Two groups of female P rats (one given water as its sole source of fluid and the other given 24-hr free-choice access to 15% ethanol and water for at least 8 weeks) were stereotaxically implanted with guide cannulae aimed at the posterior VTA. One week after surgery, rats were placed in standard two-lever (active and inactive) operant chambers and connected to the microinfusion system. Depression of the active lever produced the infusion of 100 nl of artificial cerebrospinal fluid (CSF) or ethanol. The ethanol-naïve and chronic ethanol-drinking groups were assigned to subgroups to receive artificial CSF or 25, 50, 75, or 125 mg/dl of ethanol (n = 6-9/dose/group) to self-infuse (FR1 schedule) during the 4-hr sessions given every other day. Results: Compared with the infusions of artificial CSF, the control group reliably (p < 0.05) self-infused 75 and 125 mg/dl of ethanol but not the lower concentrations. The ethanol-drinking group had significantly (p < 0.05) higher self-infusions of 50, 75, and 125 mg/dl of ethanol than artificial CSF during the four acquisition sessions; the number of infusions of all three doses was higher in the ethanol-drinking group than in the ethanol-naive group. Both groups decreased responding on the active lever when artificial CSF was substituted for ethanol, and both groups demonstrated robust reinstatement of responding on the active lever when ethanol was restored. Conclusions: Chronic ethanol drinking by P rats increased the sensitivity of the posterior VTA to the reinforcing effects of ethanol.

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KW - Ethanol Reward

KW - Intracranial Self-Administration

KW - Neuroadaptations

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