Minimal exposure to ethanol increases ethanol preference in Maudsley reactive male rats.
Male Maudsley reactive (MR/Har) rats often exhibit marked ethanol or alcohol preference (AP) after forced (one-bottle) exposure to 10% [volume/volume (vol./vol.)] ethanol, but exhibit variable AP without this exposure. In this study, we examined manipulations of one-bottle exposure to ethanol (10% ethanol as the sole source of fluid) in three experiments. In Experiment 1, we recorded voluntary consumption of 10% ethanol during 5 weeks of two-bottle choice in male and female MR/Har rats after 0, 1, 2, 3, or 4 days of one-bottle ethanol exposure. The results showed that, in male rats, one day of one-bottle exposure was as effective as multiple days in increasing AP relative to findings for ethanol-naive (control) rats. Female rats were not affected by one-bottle exposure. They drank equal amounts of ethanol across all groups and in greater amounts than observed for male rats (relative to body weight). The results of Experiment 2 supported the suggestion that 18 h of exposure to ethanol was similar to 24 h of exposure for increasing subsequent ethanol consumption, and that 12 h of exposure increased AP relative to findings for ethanol-naive rats, but on a delayed basis and at a lower level than that observed for 24 h of exposure. In Experiment 3, we tested whether these increases in ethanol consumption, observed in male MR/Har rats after one-bottle exposure to ethanol, might be related to habituating to an unpalatable substance. Thus, rats had one-bottle tests with either a 10% ethanol solution (as in earlier studies) or a 0.01 mmol quinine solution, after which groups of rats were tested for voluntary consumption (two-bottle test) of one of these solutions and water. Results showed that although rats in the quinine-exposed group drank more fluid than that consumed by rats in the ethanol-exposed group during the one-bottle period, rats preferred ethanol to water and avoided quinine relative to water during the 5 weeks of two-bottle choice. The results seem to indicate that relatively small amounts of 10% ethanol can markedly increase subsequent AP in male MR/Har rats, and that this increase in AP does not seem to be attributable to a process of habituating to an unpalatable fluid.
Adams
Nelson
N
Department of Social Sciences, Winston-Salem State University, 601 Martin Luther King, Jr. Drive, NC 27110, USA. adamsn@wssu.edu
Campbell
Santiba D
SD
Mitchell
Pamela S
PS
D000428:Alcohol Drinking / Q000235:genetics / Q000523:psychology*; D000818:Animals; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D002755:Choice Behavior / Q000187:drug effects / Q000502:physiology; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D008297:Male; D011803:Quinine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012727:Sex Characteristics; D013649:Taste / Q000502:physiology
D002492:Central Nervous System Depressants; D000431:Ethanol; D011803:Quinine