Repeated ethanol administration modifies the temporal structure of sucrose intake patterns in mice: effects associated with behavioral sensitization.
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 gamma-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.
Pastor
Raúl
R
Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA. raul.pastor@uji.es
Kamens
Helen M
HM
McKinnon
Carrie S
CS
Ford
Matthew M
MM
Phillips
Tamara J
TJ
D000435:Alcoholic Intoxication / Q000503:physiopathology; D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects*; D001418:Baclofen / Q000494:pharmacology; D001921:Brain / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology*; D018755:GABA Agonists / Q000494:pharmacology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009042:Motivation / Q000187:drug effects*; D009043:Motor Activity / Q000187:drug effects*; D011930:Reaction Time / Q000187:drug effects; D018080:Receptors, GABA-B / Q000187:drug effects; D013395:Sucrose / Q000008:administration & dosage*
D018755:GABA Agonists; D018080:Receptors, GABA-B; D000431:Ethanol; D013395:Sucrose; D001418:Baclofen