Although numerous studies have examined the neurotoxicity of acrylamide in adult animals,the effects on neuronal development in the embryonic and lactational periods are largely unknown.Thus,we examined the toxicity of acrylamide on neuronal development in the hippocampus of fetal rats during pregnancy.Sprague-Dawley rats were mated with male rats at a 1:1 ratio.Rats were administered 0,5,10 or 20 mg/kg acrylamide intragastrically from embryonic days 6–21.The gait scores were examined in pregnant rats in each group to analyze maternal toxicity.Eight weaning rats from each group were also euthanized on postnatal day 21 for follow-up studies.Nissl staining was used to observe histological change in the hippocampus.Immunohistochemistry was conducted to observe the condition of neurites,including dendrites and axons.Western blot assay was used to measure the expression levels of the specific nerve axon membrane protein,growth associated protein 43,and the presynaptic vesicle membrane specific protein,synaptophysin.The gait scores of gravid rats significantly increased,suggesting that acrylamide induced maternal motor dysfunction.The number of neurons,as well as expression of growth associated protein 43 and synaptophysin,was reduced with increasing acrylamide dose in postnatal day 21 weaning rats.These data suggest that acrylamide exerts dose-dependent toxic effects on the growth and development of hippocampal neurons of weaning rats. Many large studies have examined the neurotoxicity of acrylamide in adult animals, the effects on neuronal development in the embryonic and lactational periods are great unknown. Thus, we examined the toxicity of acrylamide on neuronal development in the hippocampus of fetal rats during pregnancy. Sprague- Dawley rats were mated with male rats at a 1: 1 ratio. Rats were administered 0, 5, 10 or 20 mg / kg acrylamide intragastrically from embryonic days 6-21. The gait scores were examined in pregnant rats in each group to analyze maternal toxicity.Eight weaning rats from each group were also euthanized on postnatal day 21 for follow-up studies. Neither the staining was used to observe histological change in the hippocampus. Immunohistochemistry was conducted to observe the condition of neurites, including dendrites and axons. Western blot assay was used to measure the expression levels of the specific nerve axon membrane protein, growth associated protein 43, and the presynaptic vesicle membrane spell suggesting that acrylamide induced maternal motor dysfunction. The number of neurons, as well as expression of growth associated protein 43 and synaptophysin, was reduced with increasing acrylamide dose in postnatal day 21 weaning rats. the data suggest that acrylamide exerts dose-dependent toxic effects on the growth and development of hippocampal neurons of weaning rats.