Department of Biology, York University, Toronto, Ontario, Canada.
Department of Biology, York University, Toronto, Ontario, Canada.
Chemosphere. 2019 Nov;235:383-390. doi: 10.1016/j.chemosphere.2019.06.133. Epub 2019 Jun 21.
The sensory-motor function in larval zebrafish (Danio rerio) following exposure to low water pH was investigated. The results suggested that acid exposure (pH 4.0-5.0; control: pH 7.4) significantly reduced the touch-evoked escape response of larval zebrafish at 3 days post fertilization (dpf). A significant number of pH 4.0-exposed larvae also exhibited a lack of escape response. Treatment with neurotransmitters showed that serotonin or acetylcholine, but not dopamine, reduced the adverse effects of acid exposure on the escape response of larvae. Co-exposure to serotonin and acetylcholine did not further improve the escape response of acid-exposed larvae, suggesting no additive effect by these neurotransmitters. Interestingly, the negative effects of acid exposure on the escape response could be completely rescued by elevating the water levels of Ca, but not NaCl. Collectively, these results suggested that acid-induced disruption in Ca balance suppressed the serotonin- and acetylcholine-mediated neuronal signaling, thereby affecting the sensory-motor function and escape response of larval zebrafish. Findings from the present study may have important implication for the survival (e.g., escape from adverse conditions) of larval fish in acid-impacted environments, particularly during early development when they are still incapable of spontaneous swimming.
研究了低水 pH 值暴露后斑马鱼幼虫的感觉-运动功能。结果表明，酸暴露（pH4.0-5.0；对照：pH7.4）显著降低了受精后 3 天（dpf）的斑马鱼幼虫的触诱发逃反应。大量 pH4.0 暴露的幼虫也表现出缺乏逃避反应。神经递质处理表明，血清素或乙酰胆碱，但不是多巴胺，降低了酸暴露对幼虫逃避反应的不利影响。血清素和乙酰胆碱的共同暴露并没有进一步改善酸暴露幼虫的逃避反应，表明这些神经递质没有相加作用。有趣的是，酸暴露对逃避反应的负面影响可以通过升高 Ca 的水位完全挽救，但不能通过升高 NaCl 的水位来挽救。总的来说，这些结果表明，酸诱导的 Ca 平衡紊乱抑制了血清素和乙酰胆碱介导的神经元信号传导，从而影响了斑马鱼幼虫的感觉-运动功能和逃避反应。本研究的结果可能对受酸影响环境中幼虫的生存（例如，逃避不利条件）具有重要意义，尤其是在早期发育阶段，它们仍然无法自发游泳。
