title: Neurotoxicological evaluation of microcystin-LR exposure at environmental relevant concentrations on nematode Caenorhabditis elegans.
abstract: Previous studies have not examined the adverse effects of microcystin-LR (MC-LR) at environmental relevant concentrations on the development and functions of nervous system. The neurotoxic effects of MC-LR exposure on neurotransmitter systems were investigated in Caenorhabditis elegans. After exposing L1 larvae to 0.1, 1, 10, and 100 μg l(-1) of MC-LR for 8 and 24 h, the adverse effects on GABAergic, cholinergic, serotonergic, dopaminergic, and glutamatergic neurons were examined. The expression levels of genes required for development and functions of GABAergic neurons were further investigated. Body bend frequency and head thrash frequency decreased significantly after MC-LR exposure for 8 h at concentrations more than 1 μg l(-1) and after MC-LR exposure for 24 h at concentrations more than 0.1 μg l(-1). Loss of GABAergic neurons increased significantly in a dose-dependent manner after MC-LR exposure at concentrations more than 0.1 μg l(-1). In contrast, no obvious neuronal losses or morphologic changes were observed in cholinergic, serotonergic, dopaminergic, and glutamatergic neurons in MC-LR-exposed nematodes. Quantitative real-time PCR assay further showed that expression levels of unc-30, unc-46, unc-47, and exp-1 genes required for development and function of GABAergic neurons decreased significantly in nematodes exposed to MC-LR at concentrations more than 0.1 or 1 μg l(-1). MC-LR at environmental relevant concentrations caused neurobehavioral defects, which may be largely due to the neuronal loss and the alterations of expression level of genes required for GABAergic neurotransmitter system in C. elegans.
authors.affiliation: Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, China.
authors.forename: Jingjuan
authors.initials: J
authors.lastname: Ju
authors.forename: Qinli
authors.initials: Q
authors.lastname: Ruan
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Li
authors.forename: Ran
authors.initials: R
authors.lastname: Liu
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Li
authors.forename: Yuepu
authors.initials: Y
authors.lastname: Pu
authors.forename: Lihong
authors.initials: L
authors.lastname: Yin
authors.forename: Dayong
authors.initials: D
authors.lastname: Wang
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects*; D059329:Cholinergic Neurons / Q000187:drug effects / Q000378:metabolism; D059290:Dopaminergic Neurons / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D059330:GABAergic Neurons / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D008124:Locomotion / Q000187:drug effects; D008387:Marine Toxins / Q000633:toxicity; D052998:Microcystins / Q000633:toxicity*; D009420:Nervous System / Q000187:drug effects* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D059326:Serotonergic Neurons / Q000187:drug effects / Q000378:metabolism
chemical_list: D008387:Marine Toxins; D052998:Microcystins; C057862:cyanoginosin LR