Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9 Canada.
Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9 Canada; Department of Physiology, University of Alberta, Edmonton, Alberta, T6G 2E9 Canada; Centre for Neuroscience, University of Alberta, Edmonton, Alberta, T6G 2E9 Canada.
Neurotoxicology. 2017 Sep;62:100-110. doi: 10.1016/j.neuro.2017.05.011. Epub 2017 Jun 3.
In this study, we examined the effects of alcohol exposure during gastrulation on zebrafish embryos, specifically focusing on excitatory synaptic activity associated with neurons (Mauthner cells) that are born during gastrulation. Furthermore, we determined whether co-treatment of alcohol and retinoic acid (RA) could prevent the effects of alcohol exposure during gastrulation. We exposed zebrafish embryos to ethanol (150mM), RA (1nM), or a combination of RA (1nM) plus ethanol (150mM) for 5.5h from 5.25h post fertilization (hpf) to 10.75 hpf (gastrulation). Ethanol treatment resulted in altered hatching rates, survivability and body lengths. Immunohistochemical analysis of Mauthner cells (M-cells) suggested that ethanol treatment resulted in smaller M-cell bodies and thinner axons, while electrophysiological recordings of AMPA miniature excitatory postsynaptic currents (mEPSCs) associated with M-cells showed that ethanol treated animals had a significantly reduced mEPSC frequency. Other mEPSC parameters such as amplitude, rise times and decay kinetics were not altered by exposure to alcohol. Locomotor studies showed that ethanol treatment resulted in altered C-bend escape responses. For instance, the C-bends of alcohol-treated fish were larger than control embryos. Thus, ethanol treatment during gastrulation altered a range of features in embryonic zebrafish. Importantly, co-treatment with RA prevented all of the effects of ethanol including survivability, body length, M-cell morphology, AMPA mEPSC frequency and escape response movements. Together these findings show that ethanol exposure during the brief period of gastrulation has a significant effect on neuronal morphology and activity, and that this can be prevented with RA co-treatment.
在这项研究中，我们研究了原肠胚形成期酒精暴露对斑马鱼胚胎的影响，特别是关注与原肠胚形成期间产生的神经元（Mauthner 细胞）相关的兴奋性突触活性。此外，我们还确定了酒精和视黄酸（RA）的共同处理是否可以预防原肠胚形成期酒精暴露的影响。我们将斑马鱼胚胎暴露于乙醇（150mM）、RA（1nM）或 RA（1nM）加乙醇（150mM）的混合物中，从受精后 5.25 小时（hpf）到 10.75 hpf（原肠胚形成期）持续 5.5 小时。乙醇处理导致孵化率、存活率和体长发生改变。Mauthner 细胞（M 细胞）的免疫组织化学分析表明，乙醇处理导致 M 细胞体变小和轴突变薄，而与 M 细胞相关的 AMPA 型微小兴奋性突触后电流（mEPSC）的电生理记录表明，乙醇处理动物的 mEPSC 频率显著降低。其他 mEPSC 参数，如振幅、上升时间和衰减动力学，不受酒精暴露的影响。运动研究表明，乙醇处理导致 C 弯逃避反应发生改变。例如，乙醇处理鱼的 C 弯大于对照胚胎。因此，原肠胚形成期的乙醇处理改变了胚胎斑马鱼的一系列特征。重要的是，RA 的共同处理预防了乙醇的所有影响，包括存活率、体长、M 细胞形态、AMPA mEPSC 频率和逃避反应运动。这些发现表明，原肠胚形成期短暂的酒精暴露对神经元形态和活性有显著影响，并且可以通过 RA 共同处理来预防。
