title: Neurobehavioral impairments caused by developmental imidacloprid exposure in zebrafish.
abstract: BACKGROUND
  Neonicotinoid insecticides are becoming more widely applied as organophosphate (OP) insecticides are decreasing in use. Because of their relative specificity to insect nicotinic receptors, they are thought to have reduced risk of neurotoxicity in vertebrates. However, there is scant published literature concerning the neurobehavioral effects of developmental exposure of vertebrates to neonicotinoids.
  
  
  METHODS
  Using zebrafish, we investigated the neurobehavioral effects of developmental exposure to imidacloprid, a prototypic neonicotinoid pesticide. Nicotine was also administered for comparison. Zebrafish were exposed via immersion in aqueous solutions containing 45 μM or 60 μM of imidacloprid or nicotine (or vehicle control) from 4h to 5d post fertilization. The functional effects of developmental exposure to both imidacloprid and nicotine were assessed in larvae using an activity assay and during adolescence and adulthood using a battery of neurobehavioral assays, including assessment of sensorimotor response and habituation in a tactile startle test, novel tank swimming, and shoaling behavior.
  
  
  RESULTS
  In larvae, developmental imidacloprid exposure at both doses significantly decreased swimming activity. The 5D strains of zebrafish were more sensitive to both nicotine and imidacloprid than the AB* strain. In adolescent and adult fish, developmental exposure to imidacloprid significantly decreased novel tank exploration and increased sensorimotor response to startle stimuli. While nicotine did not affect novel tank swimming, it increased sensorimotor response to startle stimuli at the low dose. No effects of either compound were found on shoaling behavior or habituation to a startling stimulus.
  
  
  CONCLUSIONS
  Early developmental exposure to imidacloprid has both early-life and persisting effects on neurobehavioral function in zebrafish. Its developmental neurotoxicity should be further investigated.
authors.affiliation: Department of Biology, Duke University, Durham, NC 27710, USA.
authors.forename: Emily B
authors.initials: EB
authors.lastname: Crosby
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC 27710, USA.
authors.forename: Jordan M
authors.initials: JM
authors.lastname: Bailey
authors.affiliation: Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA.
authors.forename: Anthony N
authors.initials: AN
authors.lastname: Oliveri
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA. Electronic address: edlevin@duke.edu.
authors.forename: Edward D
authors.initials: ED
authors.lastname: Levin
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D018678:Cholinergic Agents / Q000633:toxicity; D005106:Exploratory Behavior / Q000187:drug effects; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D007093:Imidazoles / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D009043:Motor Activity / Q000187:drug effects; D000073943:Neonicotinoids; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D009574:Nitro Compounds / Q000633:toxicity*; D013216:Reflex, Startle / Q000187:drug effects; D012919:Social Behavior; D013550:Swimming; D015027:Zebrafish / Q000254:growth & development*
chemical_list: D018678:Cholinergic Agents; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D018722:Nicotinic Agonists; D009574:Nitro Compounds; C082359:imidacloprid; D009538:Nicotine
keywords: Behavior; Imidacloprid; Neonicotinoid; Neurodevelopment; Nicotine; Zebrafish