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Voluntary Ethanol Drinking During the First Three Postnatal Weeks in Lines of Rats Selectively Bred for Divergent Ethanol Preference
Author(s) -
McKinzie D.L.,
Cox R.,
Murphy J.M.,
Li T.K.,
Lumeng L.,
McBride W.J.
Publication year - 1999
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.1999.tb04088.x
Subject(s) - ethanol , preference , turnover , psychology , biology , zoology , biochemistry , economics , mathematics , statistics , management
Background : Using a procedure first developed by Hall (1979), we examined ethanol self‐administration in preweanling pups from Wistar rats and in lines of rats selectively bred for divergent ethanol preference (alcohol‐preferring P, alcohol‐nonpreferring NP, high‐alcohol‐drinking HAD‐1 and ‐2, and low‐alcohol‐drinking LAD‐2) to determine if factors contributing to high and low alcohol intakes arc present early in development. Methods : From postnatal days 5 to 20, nondeprived male and female rat pups received 30 min daily access to either water or a 15% (v/v) ethanol solution. In each daily session, pups were placed in a heated chamber containing Kimwipes soakcd with a water or ethanol solution. Pups were weighed before and after each session, and intake levels were calculated as a percentage of body weight change. Results : Similar to previous reports, Wistar pups exhibited over a 2‐fold higher level of ethanol ingestion than water on postnatal days 9 through 14, with ethanol intakes approaching 3 g/kg body weight. When the drinking patterns of the selected lines were examincd, only the HAD replicate lines showed a comparable preference for ethanol versus water during the preweanling period. The ethanol consumption of P, NP, and LAD lines was not consistently distinguishable from water intake levels. To reveal whether early ethanol exposure would influence later ethanol drinking behavior, a subset of HAD and LAD rat pups received free‐choice ethanol access upon weaning. Although the divergent ethanol preference between high‐ and low‐alcohol‐drinking lines was evident within the first 4 days of access (>4 g/kg/day for HAD; <2 g/kg/day for LAD). preweanling ethanol exposure did not alter the acquisition or maintenance of ethanol drinking in cither line. Conclusions : Overall, these results suggest that (a) the enhanced ethanol ingestion observed during the middle portion of the preweanling period is a robust phenomenon and generalizes across nonselected strains of rats, (b) selective breeding for divergent alcohol preference has arrested this age‐specific effect in all hut the HAD lines of rats, and (c) early ethanol exposure does not alter genetic dispositions for later high or low alcohol prefercnce.