Chronic prenatal exposure to phenobarbital and long-term behavior effects on mice offspring.

OBJECTIVE

To assess the impact of chronic prenatal exposure to phenobarbital on long-term behavior in mice offspring.

METHODS

Twenty-eight C3H/He mice were randomized to receive diet chow containing either a daily therapeutic dose of phenobarbital (2.5 mg in 10-g chow) or a placebo for 1 week before mating and throughout gestation. Offspring from eight litters of each treatment group were evaluated using motor function, arousal/motivation, anxiety-provoking and cognition tasks.

RESULTS

No significant differences between groups were found in duration of gestation, litter size and birth weights. Fewer counts in a locomotor chamber were observed in phenobarbital-exposed offspring (524 +/- 31 vs. 688 +/- 54 for 60 min, p < 0.02; 4174 +/- 229 vs. 5230 +/- 406 for 22 h, p < 0.05). Initial reactions to a startle were more apparent among phenobarbital-exposed offspring (p < 0.03). Impaired co-ordination of hindlimbs was observed in the phenobarbital-exposed offspring during the wire maneuver (p < 0.001). Fewer entries into the mirrored chamber were observed after phenobarbital exposure (2.1 vs. 4.5; p < 0.05). Exposure to phenobarbital was not found to affect responses to learning and memory tasks (homing, tube runway, water runway, Morris maze).

CONCLUSION

Although cognition was unaffected by prenatal exposure to phenobarbital, subtle effects on locomotor activity, hindlimb co-ordination and responses to anxiety-provoking conditions require human correlation.