The action of thalidomide on the peripheral nervous system of the embryo.

The mode of teratogenic action of thalidomide is unknown. A new radiological interpretation of thalidomide-induced limb malformations suggested that pathological changes should be sought in the sensory ganglia. Newborn rabbits with thalidomide-induced limb defects were examined histologically, and failure of maturation of dorsal root ganglion cells was demonstrated. This neuronal immaturity supports the radiological hypothesis of embryonic neuropathy, which is proposed as the underlying pathology of the limb deformities due to thalidomide.