PRECLINICAL STUDY: FULL ARTICLE: Repeated ethanol administration modifies the temporal structure of sucrose intake patterns in mice: effects associated with behavioral sensitization

Authors

  • Raúl Pastor,

    Corresponding author
    1. Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA,
    2. Portland Alcohol Research Center, Portland, OR, USA,
    3. Area de Psicobiología, Universitat Jaume I, Castellón, Spainand
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  • Helen M. Kamens,

    1. Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA,
    2. Portland Alcohol Research Center, Portland, OR, USA,
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    • *

      Present address: Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80303, USA.

  • Carrie S. McKinnon,

    1. Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA,
    2. Portland Alcohol Research Center, Portland, OR, USA,
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  • Matthew M. Ford,

    1. Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA,
    2. Portland Alcohol Research Center, Portland, OR, USA,
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  • Tamara J. Phillips

    1. Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA,
    2. Portland Alcohol Research Center, Portland, OR, USA,
    3. Portland VA Medical Center, Research Service, Portland, OR, USA
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Raúl Pastor, Area de Psicobiología, Universitat Jaume I, Avenue, Sos Baynat s/n, 12071, Castellón, Spain. E-mail: raul.pastor@uji.es

ABSTRACT

Neuroadaptations supporting behavioral sensitization to abused drugs are suggested to underlie pathological, excessive motivation toward drugs and drug-associated stimuli. Drug-induced sensitization has also been linked to increased appetitive responses for non-drug, natural reinforcers. The present research investigated whether ethanol (EtOH)-induced neural changes, inferred from psychomotor sensitization, can modify consumption and intake dynamics for the natural reinforcer, sucrose. The effects of EtOH-induced sensitization in mice on the temporal structure of sucrose intake patterns were measured using a lickometer system. After sensitization, sucrose intake dynamics were measured for 1 hour daily for 7 days and indicated more rapid initial approach and consumption of sucrose in EtOH-sensitized groups; animals showed a shorter latency to the first intake bout and an increased number of sucrose bottle licks during the initial 15 minutes of the 1-hour sessions. This effect was associated with increased frequency and size of bouts. For the total 1-hour session, sucrose intake and bout dynamics were not different between groups, indicating a change in patterns of sucrose intake but not total consumption. When sensitization was prevented by the γ-aminobutyric acid B receptor agonist, baclofen, the increased rate of approach and consumption of sucrose were also prevented. Thus, EtOH-induced sensitization, and not the mere exposure to EtOH, was associated with changes in sucrose intake patterns. These data are consistent with current literature suggesting an enhancing effect of drug-induced sensitization on motivational processes involved in reinforcement.

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