Behavioral effects of prenatal exposure to ethylene dibromide

Pregnant female Long-Evans hooded rats were exposed to 0, 0.43, 6.67, or 66.67 ppm ethylene dibromide (EDB) via inhalation for four hours/day three days/week from Day 3 to Day 20 of gestation. The 66.67 ppm dose produced an increase in defecation during exposure, decreased gestational weight gain, and enhanced rotorod performance and T-maze brightness discrimination acquisition in the offspring. Similar changes were noted in the dams and offspring exposed to 6.67 ppm, but the magnitude of the effects was reduced. No effects of exposure to 0.43 ppm were detected, nor were litter size, litter composition, nest building, pup retrieval, DRL-20 acquisition, straight alley running speed, or passive avoidance affected by exposure to any dose. We suggest that the behavioral effects of the medium and high doses may be secondary to stress reactions in the dams to exposure to these doses.