Ethanol Preference in the Harrington Derivation of the Maudsley Reactive and Non-Reactive Strains

Department of Social Science, Winston Salem State University, North Carolina 27110.
Alcoholism Clinical and Experimental Research (Impact Factor: 3.21). 04/1991; 15(2):170-4. DOI: 10.1111/j.1530-0277.1991.tb01849.x
Source: PubMed


Ethanol intake was explored in the Harrington derivation of the Maudsley Reactive and Maudsley Non-Reactive rat strains (MR/Har and MNRA/Har). When 5% and 10% ethanol solutions were presented as the sole source of fluid (1-bottle test), MR/Har rats, respectively, ingested 15% more, or 9% less, than their baseline water intake, whereas MNRAs ingested 6% less, or 42% less than their baseline intake. However, because MNRA/Har rats drank significantly more water than MR/Har's under ad libitum conditions (MNRA/Har, 46.6 +/- 1.83 ml; MR/Har 32.45 +/- 1.64 ml/24 hr), males and females of the two strains ingested a similar amount of ethanol in the 1-bottle test (5% ethanol, 4-7; 10% ethanol, 6-12 g/kg body weight/24 hr). In 2-bottle free-choice tests administered after an extended period of forced ethanol consumption, MR/Har male and female rats exhibited a strong ethanol preference (X = 80%) and consumed a larger amount of ethanol (MR/Har, 7-13; MNRA/Har, 6-9 g/kg body weight/24 hr) than MNRA/Har's. Across all conditions, females of both strains ingested a greater relative amount of ethanol than males. The strain difference in ethanol preference was found to be independent of prior exposure to ethanol because it was also found when 2-bottle free-choice tests were carried out in naive animals (Experiment 2). The pattern of development of ethanol preference in individual animals was characterized by abrupt onset, after variable periods of exposure to the 2-bottle choice test, and maintenance of strong ethanol preference thereafter. The extensive behavioral and biological definition of the Maudsley strains is a valuable asset in attempting to elucidate the biobehavioral correlates of ethanol preference.

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    • "Therefore, they might not necessarily be co-selected when animals are selectively bred either for differences in emotionality or for differences in alcohol preference. For example, anxiety levels and alcohol drinking seem to correlate in sP (sardinian alcohol-preferring ) and in Indianapolis P (preferring) rats (Colombo et al. 1995; Stewart et al. 1993), but seem to be less consistently related in the Finnish alcohol-preferring AA (Alko Alcohol) rats (Tuominen et al. 1990; Fahlke et al. 1993; Möller et al. 1997b) and in MR (Maudsley reactive) rats (Brewster 1968, 1969; Adams et al. 1991; Overstreet et al. 1993). This interpretation is supported by a recent factor analysis of 18 behavioral measures from nine pairs of alcohol-preferring and nonpreferring rats (Overstreet et al. 1997). "
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    ABSTRACT: According to the tension reduction hypothesis, individuals with an elevated anxiety level may be more sensitive to the anxiolytic effects of alcohol and may, therefore, have a higher predisposition to consume alcohol. To examine this hypothesis, we studied the drinking behavior as well as the sensitivity to the anxiolytic effect of alcohol in two rat lines that were bred and selected for differences in anxiety-related behavior on the elevated plus-maze: the extremely anxious HAB (high anxiety-related behavior) and the non-anxious LAB (low anxiety-related behavior) lines. Alcohol self-administration and the occurrence of an alcohol deprivation effect were studied in female and male HAB and LAB rats in a free-choice, 4-bottle home cage paradigm. The sensitivity of HAB and LAB rats to the anxiolytic effect of alcohol was assessed by testing their behavior on the elevated plus-maze after an acute application of ethanol. During the first days of voluntary ethanol drinking, the ethanol intake and preference of female LABs was significantly higher than that of female HABs. Although not statistically significant, the same trend could be seen in male LABs. Moreover, male as well as female LAB but not HAB rats showed a significant alcohol deprivation effect after abstinence. There were no differences when saccharin was presented to naive animals, indicating that the different ethanol drinking behavior of HAB and LAB rats does not represent a general difference in the consumption of new liquids. Application of ethanol resulted in an anxiolytic effect in HAB but not in LAB rats on the elevated plus-maze. In summary, increased inborn anxiety and voluntary ethanol consumption of HAB and LAB rats were correlated to some extent; however, this relationship was a negative one. It is concluded that, although such a relationship might exist in some individuals, increased levels of inborn anxiety and alcohol consumption are not necessarily related.
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    • "Together these findings suggest that female neonates are more sensitive than males to ethanol. Although gender differences in responsiveness to ethanol are common in adult rats (Adams et al., 1991; Lancaster and Spiegel, 1992; Li and Lumeng, 1984), they have not been observed previously in preweanling animals (Chotro et al., 1996; Lee et al., 1998; McKinzie et al., 1999; Molina et al., 1999). Given strong interaction between gender and ethanol concentration associated with ethanol intake (Varlinskaya et al., 1999), the effectiveness of orally processed ethanol as a US (experiments 5 and 6), and the absence of an effect of gender when ethanol had minimal orosensory consequences but was nevertheless an effective US and reinforcer (experiment 8), it is likely that neonatal male and female rats perceive orosensory properties of ethanol differently . "
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    • "These include the Chilean UChB (Mardones and Segovia-Requelme, 1983), Finnish AA (Kiianmaa et al, 1991), Indiana P (Li et al., 1987), and Sardinian sP (Colombo, 1997) rat lines, in comparison with their corresponding -non-preferring control counterparts (UChA, ANA, NP, and sNP respectively). Two other rat strains have also been identified as alcohol-preferring, namely the Fawn-Hooded (Rezvani et al., 1990; Overstreet et al, 1993) and the Maudsley Reactive (Satinder, 1972; Adams et al., 1991) rats, in comparison with ordinary Wistar (Sprague-Dawley) and the 'Present address: Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan. "Author to whom correspondence should be addressed. "
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