Late embryonic exposure to all-trans retinoic acid induces a pattern of motor deficits unrelated to the developmental stage.

The present study extends previous investigations examining the behavioral outcomes of all-trans retinoic acid (RA) exposure at embryonic (E) days 14-16. A sublethal dose (2.5 mg/kg b.w.) compatible with high neonatal survival sufficient to supply offspring for later behavioral testing, was used. The results show that E14-16 RA exposure, similar to E8-10 or E11-13 (previous studies), impairs locomotor activity (open field test) as well as motor coordination and motor learning (rotarod/accelerod task) in young-adult rats. The results provide further evidence that RA exposure induces a pattern of motor deficits which are not strictly related to the embryonic stage, compatible with the protracted developmental profile of the cerebellum.