Background: Selectively bred rodent lines are valuable tools for investigating gene x environment interactions related to risk for alcoholism in humans. Early maternal environment is one particular factor known for critically influencing neural, hormonal, and behavioral outcomes in adulthood. Cross-fostering is a procedure that may be used to explore the role of genotype-dependent maternal influences on phenotypic variability in adulthood. The purpose of these experiments was to examine the effects of cross-fostering on free-choice alcohol drinking and correlated responses to selection for alcohol preference in mice selectively bred for high- (HAP2) and low- (LAP2) alcohol preference. Methods: Mice were assigned to one of the following treatments: SHAM (pups that were fostered to their original biological mother), IN (pups that were fostered to a different mother of the same line), and CROSS (pups that were fostered to a mother of a different line). Mice were tested in adulthood for (1) free 24-hr access to alcohol for a period of 28 days; (2) expression of the acoustic startle response and fear-potentiated startle (FPS) and (3) handling-induced convulsions (HICs) during acute alcohol withdrawal. Results: Overall, the expression of the alcohol preference selection phenotype was robust in all groups (HAP2>LAP2). Cross-fostering produced a moderate but significant reduction in g/kg alcohol drinking and preference scores in HAP2 mice (CROSSLAP2), FPS (HAP2>LAP2), HICs (LAP2>HAP2). Conclusions: It appears that maternal environment can modify the expression of the high alcohol preference phenotype in HAP2 selectively bred mice. These results suggest a gene x environment interaction with respect to the expression of the high alcohol preference selection phenotype but not correlated responses to selection.


This is the author accepted manuscript of Barrenha, G.D., & Chester, J.A. (2012). Effects of cross-fostering on alcohol preference and correlated responses to selection in high- and low-alcohol preferring mice. Alcoholism: Clinical and Experimental Research, 36(12), 2065-73. Epub 2012 May 16. 2012. The published version can be found at http://onlinelibrary.wiley.com/doi/10.1111/j.1530-0277.2012.01839.x/abstract.


alcohol drinking, cross-fostering, fear-potentiated startle, alcohol withdrawal, selected lines

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