Teratogenic effects of lamotrigine on rat fetal brain: a morphometric study.

A study of the teratogenic activity of an antiepileptic drug - lamotrigine - was carried out in the brain of fetuses of rats who had received the drug. The dosage levels studied corresponded to four times the median effective dose (ED50) in rats. The drug was administered during the organogenesis period. Rats were sacrificed one day prior to term and fetuses were macroscopically examined, weighted and cephalic segments sectioned (Wilson technique), for histological study by stereological analysis, using Merz's grid for drawing and point counts. Cortex, subcortex, ependyma and lateral ventricles were analyzed. The same methodology was applied to the control group; data were compared with by the non-parametric Mann-Whitney statistical analysis test. Results showed that fetuses of the experimental group had reduced body weight at birth, increased volume and diameter of the cerebral structure, increased density of the subcortical layer, and ventricle dilatation. Possible mechanisms of this teratogenicity were discussed.