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Ethanol Drinking Microstructure of a High Drinking in the Dark Selected Mouse Line

Authors

  • Amanda M. Barkley-Levenson,

    Corresponding author
    1. Portland Alcohol Research Center, VA Medical Center, Portland, Oregon.
    • Department of Behavioral Neuroscience, Oregon Health and Science University
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  • John C. Crabbe

    1. Department of Behavioral Neuroscience, Oregon Health and Science University
    2. Portland Alcohol Research Center, VA Medical Center, Portland, Oregon.
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Amanda Barkley-Levenson, Portland Alcohol Research Center, Department of Behavioral Neuroscience, Oregon Health & Science University, and VA Medical Center, Portland, Oregon 97239; Tel.: 503-220-8262 (Ext 54439); Fax: 503-494-6877; E-mail: barkleya@ohsu.edu

Abstract

Background

The High Drinking in the Dark (HDID) selected mouse line was bred for high blood ethanol (EtOH) concentration (BEC) following the limited access drinking in the dark (DID) test and is a genetic animal model of binge-like drinking. This study examines the microstructure of EtOH drinking in these mice and their control line during 3 versions of the DID test to determine how drinking structure differences might relate to overall intake and BEC.

Methods

Male mice from the HDID-1 replicate line and HS/Npt progenitor stock were tested in separate experiments on 2- and 4-day versions of the DID test, and on a 2-day 2-bottle choice DID test with 20% EtOH and water. Testing took place in home cages connected to a continuous fluid intake monitoring system, and drinking during the DID test was analyzed for drinking microstructure.

Results

HDID-1 mice had more drinking bouts, shorter interbout interval, larger bout size, greater total EtOH intake, and higher BECs than HS/Npt mice on the second day of the 2-day DID test. The 4-day DID test showed greater bout size, total EtOH intake, and BEC in the HDID-1 mice than the HS/Npt mice. Total EtOH intake and BECs for the HDID-1 mice in the DID tests averaged 2.6 to 3.0 g/kg and 0.4 to 0.5 mg/ml, respectively. The 2-bottle choice test showed no genotype differences in drinking microstructure or total consumption but did show greater preference for the EtOH solution in HDID-1 mice than HS/Npt.

Conclusions

These results suggest that inherent differences in EtOH drinking structure between the HDID-1 and HS/Npt mice, especially the larger bout size in the HDID-1 mice, contribute to the difference in intake during the standard DID test.

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