Positive association between ethanol consumption and anxiety-related behaviors in two selected rat lines

The Floripa H and L rat lines were selectively bred, respectively, for high and low scores of locomotion in the central aversive area of an open field (OF), which is a putative index of experimental anxiety. In the present study, we used these lines to examine the relationship between anxiety-related behaviors and ethanol intake through the use of three animal tests used to investigate anxiety (OF, elevated plus maze, and black/white box) and one oral ethanol consumption procedure. Males and females of the Floripa L line were more anxious-like than their counterparts in the three behavioral tests. No line differences in the tests of taste control solutions (saccharin and quinine) and forced ethanol (10%) were found. However, Floripa L female rats consumed more ethanol than their Floripa H counterparts at concentrations of 6 and 10% in a two-bottle choice protocol. Moreover, Floripa L females showed a higher ratio of ethanol to total fluids consumed, regardless of the concentration offered, than all other subgroups (males of both lines and Floripa H females). Males showed no line differences for ethanol consumption. Taken together, the results of this study confirm that there are important sex differences in both anxiety-related behaviors and ethanol consumption. Accordingly, these data suggest a positive genetic relationship between anxiety-related behaviors and ethanol intake, at concentrations of 6 and 10%, in females but not in males. This supports the use of both sexes in animal experiments involving anxiety- and ethanol-related behaviors. Finally, the results and the existing literature indicate that selectively bred laboratory animals constitute a useful tool in the search for genes influencing both anxiety and ethanol consummatory behavior.