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

Abstract

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.