The effects of moderate prenatal ethanol exposure on anxiety in a rodent model.

Fetal Alcohol Spectrum Disorders encompass a range of behavioral and structural consequences following exposure to ethanol in utero. The goal of this study was to develop a rodent model of voluntary ethanol consumption during pregnancy. Rats were given access to 5% ethanol in a sweetened saccharin solution for 4 hours daily, during the dark cycle. Exposure began prior to breeding and was continued until 48 hours prior to birth. A pair-fed and non-treated control group were also included. Two behavioral tests were used to measure anxiety: a marble burying task during adolescence (postnatal days (PND) 42-46) and an open field in young adulthood (PND 75-85). Offspring were placed in a cage with 20 marbles and the number buried was recorded. Increased marble burying is significantly correlated with increased anxiety. In the open field test, offspring were tested in a round open-field (OF) chamber with a video-tracking system recording their activity for 20 min over 2 test days. An important measure of anxiety in the OF is the number of entries into the center of the chamber which is inversely correlated with anxiety. Data from both of these experiments suggested that females exposed to low doses of ethanol during development were more anxious than controls as measured by more marbles buried and fewer entries into the center of the OF. This pattern was not observed in males but does suggest that exposure to low doses of ethanol during prenatal development may increase anxiety in the female offspring that persists across different test paradigms and ages. These results provide further support for including both males and females in tests of ethanol on development. Furthermore, very little data is currently available on the consequences of low dose ethanol exposure and so further work is clearly needed