Biology Department, Sultan Qaboos University, Muscat, PO Box 36, 123, Oman.
Biology Department, Sultan Qaboos University, Muscat, PO Box 36, 123, Oman.
Environ Pollut. 2021 Feb 1;270:116164. doi: 10.1016/j.envpol.2020.116164. Epub 2020 Nov 27.
Despite publication of numerous of papers, the effects of fluoxetine on fish behaviour remains mired in controversy and contradiction. One reason for this controversy is that fluoxetine displays distinct and opposing acute and chronic effects. A second reason is that most studies have been limited to two or at the most three concentrations. To address these deficiencies we exposed adult zebrafish, both single females and shoals consisting of one male and two females, to seven fluoxetine concentrations, ranging from 5 ng/L to 5 μg/L and measured their swimming behaviour, and response to a conspecific alarm substance (CAS) at seven, 14 and 28 days. We also measured the light startle response of unexposed F1 larvae at days seven and 28 post-hatch and the response to CAS at day 28. On day 7 fluoxetine decreased swimming speed at concentrations ≥500 ng/L. After addition of CAS fish exposed to 5, 500 and 1000 ng/L decreased swimming, while fish exposed to 10, 500 and 1000 ng/L significantly increased time motionless. On day 14 only fish exposed to 50 ng/L were significantly slower than controls before addition of CAS, but afterwards fish exposed to 5, 50, 1000 and 5000 ng/L showed significant differences from controls. On day 28 fish exposed to 50 and 5000 ng/L had slower average swimming speeds than controls before addition of CAS. After addition all fish except controls and those exposed to 500 ng/L showed decreased average speed. At seven days post-hatch, F1 larvae whose parents were exposed to 100 ng/L showed significantly higher activity than controls and those exposed to 500 ng/L fluoxetine showed lower activity in the light startle response. This study shows that the effects of fluoxetine vary with time and also in a non-monotonic manner. We suggest that the complex nature of the serotonergic system with multilateral effects at the genomic, biochemical and physiological levels interacting with environmental stimuli result in non-linear dose-response behavioural patterns.
尽管已经发表了大量的论文，但氟西汀对鱼类行为的影响仍然存在争议和矛盾。造成这种争议的原因之一是氟西汀表现出明显的、相反的急性和慢性作用。另一个原因是大多数研究仅限于两种或最多三种浓度。为了解决这些缺陷，我们将成年斑马鱼（包括单只雌性和由一只雄性和两只雌性组成的鱼群）暴露于七种氟西汀浓度中，范围从 5ng/L 到 5μg/L，并测量它们的游泳行为以及对同种警报物质（CAS）的反应在第 7、14 和 28 天。我们还测量了未暴露的 F1 幼虫在孵化后第 7 天和第 28 天的光惊跳反应以及在第 28 天对 CAS 的反应。在第 7 天，氟西汀在浓度≥500ng/L 时降低了游泳速度。添加 CAS 后，暴露于 5、500 和 1000ng/L 的鱼的游泳速度下降，而暴露于 10、500 和 1000ng/L 的鱼的静止时间显著增加。在第 14 天，只有暴露于 50ng/L 的鱼在添加 CAS 之前比对照组明显较慢，但之后暴露于 5、50、1000 和 5000ng/L 的鱼与对照组有显著差异。在第 28 天，暴露于 50 和 5000ng/L 的鱼的平均游泳速度比对照组在添加 CAS 之前慢。添加 CAS 后，除对照组和暴露于 500ng/L 的鱼外，所有鱼的平均速度都有所下降。在孵化后第 7 天，其父母暴露于 100ng/L 的 F1 幼虫的活动明显高于对照组，而暴露于 500ng/L 氟西汀的幼虫的光惊跳反应活动较低。这项研究表明，氟西汀的作用随时间而变化，并且呈非单调方式变化。我们认为，5-羟色胺能系统的复杂性质，在基因组、生化和生理水平上具有多方面的影响，并与环境刺激相互作用，导致非线性剂量-反应行为模式。
