A Study Examining Intravenous Ethanol-Conditioned Place Preference in C57BL/6J Mice

• Published in: Alcoholism, clinical and experimental research Vol. 21; no. 9; pp. 1661 - 1666
• Main Authors: Kelley, Brian M., Bandy, Angela-Leigh E., Middaugh, Lawrence D.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.12.1997; Lippincott Williams & Wilkins
• Subjects: Alcohol; Alcoholism and acute alcohol poisoning; Animals; Behavior, Animal - drug effects; Biological and medical sciences; C57BL/6J Mice; Conditioned Place Preference; Conditioning, Classical - drug effects; Conditioning, Operant - drug effects; Discrimination Learning - drug effects; Drug Discrimination; Ethanol - administration & dosage; Ethanol - pharmacology; Infusions, Intravenous; Injections, Intraperitoneal; Intravenous Ethanol; Medical sciences; Mice; Mice, Inbred C57BL; Reward; Self Administration; Toxicology; Vertebrata; Intraperitoneal administration; Mammalia; Intravenous administration; Ethanol; Conditioned place preference; Mouse; Animal; Rodentia; Reinforcement; Instrumental conditioning; Route of administration
• ISSN: 0145-6008; 1530-0277
• DOI: 10.1111/j.1530-0277.1997.tb04504.x

The reinforcing effects of intravenous (IV) ethanol were examined in C57BL/6J (C57) mice with a conditioned‐place‐preference (CPP) paradigm. Before CPP testing, adult mice underwent jugular catheterization. On the following day, subjects were acclimated to a two‐compartment CPP chamber. A 15‐min nondrug pretest was conducted to determine compartment preference. For the treatment group, IV ethanol [30% (v/v), 3.4 μl/min, 25 min] was paired with the nonpreferred compartment, whereas IV saline was paired with the preferred compartment. The control group received IV saline in both compartments. Two conditioning sessions were conducted per day (0900 and 1500), and the order of the infusions was counterbalanced across subjects. The drug‐free posttest was identical to the pretest, except that it occurred on the day after the final drug/compartment pairing. The entire procedure required 6 days. After just two pairings with ethanol, with a cumulative ethanol dose of only 0.82 g/kg/day, significant CPP was noted in the treatment group, whereas no change in compartment preference was noted for the control group. A separate group of C57 mice were trained to discriminate intraperitoneal ethanol (1.5 g/kg) from saline using a two‐lever drug discrimination paradigm. After training was complete, these mice also underwent jugular catheterization. Substitution testing was conducted with IV ethanol [30% (v/v), 6.4 μl/min, 12 min] and saline. The results indicate that the subjective effects of ethanol did not differ according to the route of administration. Together, these experiments provide evidence that ethanol is rewarding for C57 mice, as indexed by ethanol CPP, and that the subjective effects of intravenously and intraperitoneally administered ethanol are similar.