Effect of prenatal exposure to styrene on the neurobehavioral development, activity, motor coordination, and learning behavior of rats.

Maternal Wistar rats were exposed via inhalation to 0, 50, or 300 ppm styrene for 6 h/day during gestation days 7 to 21, and offspring were subsequently evaluated in several neurobehavioral tests. Preliminary results with a small number of litters revealed significant dose-dependent effects in tests performed prior to weaning (surface righting, pivoting locomotion, and bar holding), as well as in tests performed after weaning (motor coordination, open-field behavior, and motor activity). Exposure to low concentrations of styrene (50 ppm) caused disturbances in motor coordination in addition to delaying some motor and reflex developments. Large doses (300 ppm) led to changes in open-field behavior and increases in spontaneous activity in addition to the delay in neurobehavioral developments. Exposure of dams to styrene did not clearly affect the learning behavior of the offspring. It was also observed that age played a role in the differences in styrene's effects on neurobehavioral function. Only subtle effects were found in both open-field behavior and motor-coordination function when compared with control rats at 120 days of age. These results suggest that the functional neurobehavioral development of progeny of dams exposed to styrene (or other solvents) should be further investigated.