title: Exposure to lead and mercury in young larvae induces more severe deficits in neuronal survival and synaptic function than in adult nematodes.
abstract: In the present study, we investigated the possibly neurotoxic effects of metal (Pb and Hg) exposure at different developmental stages on neuronal loss in the GABAergic nervous system and synaptic functions in the nematode Caenorhabditis elegans. Our data suggest that neuronal survival in GABAergic neurons and cholinergic transmission were relatively stable during development in nematodes. Moreover, neurodegeneration, as shown by the neuronal loss and dorsal/ventral cord gaps, was more severely induced by Pb and Hg exposure at the L1 through L3 larval stages than at the L4 larval and young-adult stages. Similarly, pre- and postsynaptic functions were more severely impaired by Pb and Hg exposure at the L1 through L3 larval stages than at the L4 larval and young-adult stages. Furthermore, both aldicarb and levamisole resistance were significantly correlated with neuronal loss, dorsal cord gap, and ventral cord gap in Pb- and Hg-exposed nematodes, suggesting that neuronal survival was noticeably correlated with synaptic function in metal-exposed nematodes during development. Therefore, younger (L1-L3) larvae show more sensitivity to neurotoxicity of neuronal survival and synaptic function than L4 larvae and young adult nematodes.
authors.affiliation: Department of Genetics and Developmental Biology, Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Southeast University Medical School, Nanjing, China.
authors.forename: X-J
authors.initials: XJ
authors.lastname: Xing
authors.forename: Q
authors.initials: Q
authors.lastname: Rui
authors.forename: M
authors.initials: M
authors.lastname: Du
authors.forename: D-Y
authors.initials: DY
authors.lastname: Wang
mesh_terms: D000367:Age Factors; D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000378:metabolism; D007814:Larva / Q000187:drug effects* / Q000378:metabolism; D007854:Lead / Q000633:toxicity*; D008627:Mercuric Chloride / Q000633:toxicity*; D009046:Motor Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009566:Nitrates / Q000633:toxicity*; D012989:Soil Pollutants / Q000633:toxicity*; D009435:Synaptic Transmission / Q000187:drug effects*; D018675:Toxicity Tests; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D009566:Nitrates; D012989:Soil Pollutants; D007854:Lead; D008627:Mercuric Chloride; D005680:gamma-Aminobutyric Acid; C017461:lead nitrate