Early embryonic ethanol exposure impairs shoaling and the dopaminergic and serotoninergic systems in adult zebrafish

Abstract

Fetal Alcohol Syndrome (FAS) is a devastating disorder accompanied by numerous morphological and behavioral abnormalities. Human FAS has been modeled in laboratory animals including the zebrafish. Recently, embryonic exposure to low doses of ethanol has been shown to impair behavior without any gross morphological alterations in zebrafish. The exposed zebrafish showed reduced responses to animated conspecific images. The effect of embryonic ethanol exposure, however, has not been investigated in a real shoal and the potential mechanisms underlying the behavioral impairment are also unknown. Here we show that a 2 hour long immersion in 0.25% and 0.50% (vol/vol) alcohol at 24 hours post fertilization significantly increases the distance among members of freely swimming groups of zebrafish when measured at 70 days post fertilization. We also show that this impaired behavior is accompanied by reduced levels of dopamine, DOPAC, serotonin and 5HIAA as quantified by HPLC from whole brain extracts. Our results demonstrate that even very low concentrations of alcohol applied for a short period of time during the development of zebrafish can impair behavior and brain function. We argue that the observed behavioral impairment is not likely to be due to altered performance capabilities, e.g. motor function or perception, but possibly to social behavior itself. We also argue that our neurochemical data represent the first step towards understanding the mechanisms of this abnormality in zebrafish, which may lead to better modeling of, and ultimately perhaps better therapies for human FAS.

Fishing for Fetal Alcohol Spectrum Disorders: Zebrafish as a Model for Ethanol Teratogenesis

“…Embryonic ethanol exposure impairs social behavior in adult zebrafish. [58][59][60][61][62] Zebrafish form social groups called shoals. 63 Research has demonstrated that a single 2-h exposure to 1% ethanol (v/v) at 24 hours postfertilization (hpf) can impair an individual's response to a virtual shoal and between groups of live zebrafish.…”

“…63 Research has demonstrated that a single 2-h exposure to 1% ethanol (v/v) at 24 hours postfertilization (hpf) can impair an individual's response to a virtual shoal and between groups of live zebrafish. 58,59,61,62 These social impairments are present in adult fish ranging in age from 4 to 24 months. 58,59,61,62 Parker et al 60 examined the effect a 0.12% developmental dose of ethanol (48 to 216 hpf-9 days) had on individual and group shoaling behavior in 4-month-old zebrafish.…”

“…58,59,61,62 These social impairments are present in adult fish ranging in age from 4 to 24 months. 58,59,61,62 Parker et al 60 examined the effect a 0.12% developmental dose of ethanol (48 to 216 hpf-9 days) had on individual and group shoaling behavior in 4-month-old zebrafish. They found both the individual's response to a social cue (five live zebrafish) and group shoaling were impaired by embryonic ethanol exposure in adult zebrafish.…”

Influences of acute ethanol exposure on locomotor activities of zebrafish larvae under different illumination

“…Ethanol treatments at concentrations up to 0.5% in AB strain zebrafish larvae at 24 hpf for 2 h not only impaired the shoaling behavior of the zebrafish at 70 dpf, but also significantly reduced the levels of DA, DOPAC, 5-HT, and 5-HIAA in the brains of the 70 dpf zebrafish (Buske & Gerlai, 2011). Acute 1-h ethanol exposure at concentrations up to 1% in 90 dpf AB strain zebrafish resulted in increased levels of DA, DOPAC, 5-HT, and 5-HIAA in the brains of the zebrafish (Chatterjee & Gerlai, 2009).…”

The developmental neurotoxicity of polybrominated diphenyl ethers: Effect of DE‐71 on dopamine in zebrafish larvae

“…All rights reserved which might cause long-lasting dysfunction in the developing brain [33]. For example, downregulation of TH and DAT has been reported upon exposure to sodium benzoate, and such changes were related to behavioral changes in developing zebrafish larvae [34].…”