Ziegler Michael, Knoll Sarah, Köhler Heinz-R, Tisler Selina, Huhn Carolin, Zwiener Christian, Triebskorn Rita
Animal Physiolgical Ecology, Eberhard-Karls-Universität Tübingen, Tübingen, Baden-Württemberg, Germany.
Effect-based Environmental Analysis, Eberhard-Karls-Universität Tübingen, Tübingen, Baden-Württemberg, Germany.
PeerJ. 2020 Mar 12;8:e8765. doi: 10.7717/peerj.8765. eCollection 2020.
Over the last two decades, there has been a constant increase in prescription rates of antidepressants. In parallel, neuroactive pharmaceuticals are making their way into aquatic environments at increasing concentrations. Among the antidepressants detected in the environment citalopram, a selective serotonin reuptake inhibitor, is one of the most commonly found. Given citalopram is specifically designed to alter mood and behaviour in humans, there is growing concern it can adversely affect the behaviour on non-target wildlife.
In our study, brown trout were exposed to citalopram (nominal concentrations: 1, 10, 100, 1000 µg/L) in two different life stages. Larvae were exposed at 7 and 11 °C from the eyed ova stage until 8 weeks post yolk sac consumption, and juvenile brown trout were exposed for 4 weeks at 7 °C. At both stages we measured mortality, weight, length, tissue citalopram concentration, behaviour during exposure and behaviour in a stressfull environment. For brown trout larvae additionally hatching rate and heart rate, and for juvenile brown trout the tissue cortisol concentration were assessed.
During the exposure, both larvae and juvenile fish exposed to the highest test concentration of citalopram (1 mg/L) had higher swimming activity and spent longer in the upper part of the aquaria compared to control fish, which is an indicator for decreased anxiety. Most probably due to the higher swimming activity during the exposure, the juveniles and larvae exposed to 1 mg/L citalopram showed decreased weight and length. Additionally, in a stressful artificial swimming measurement device, brown trout larvae displayed the anxiolytic effect of the antidepressant by reduced swimming activity during this stress situation, already at concentrations of 100 µg/L citalopram. Chemical analysis of the tissue revealed rising citalopram tissue concentrations with rising exposure concentrations. Tissue concentrations were 10 times higher in juvenile fish compared to brown trout larvae. Fish plasma concentrations were calculated, which exceeded human therapeutic levels for the highest exposure concentration, matching the behavioural results. Developmental parameters like hatching rate and heart rate, as well as mortality and tissue cortisol content were unaffected by the antidepressant. Overall, we could trace the pharmacological mode of action of the antidepressant citalopram in the non-target organism brown trout in two different life stages.
在过去二十年中，抗抑郁药的处方率持续上升。与此同时，神经活性药物正以越来越高的浓度进入水生环境。在环境中检测到的抗抑郁药中，选择性5-羟色胺再摄取抑制剂西酞普兰是最常见的一种。鉴于西酞普兰专门设计用于改变人类的情绪和行为，人们越来越担心它会对非目标野生动物的行为产生不利影响。
在我们的研究中，褐鳟在两个不同的生命阶段暴露于西酞普兰（标称浓度：1、10、100、1000μg/L）。幼虫从眼卵期开始在7℃和11℃下暴露，直到卵黄囊消耗后8周，幼年褐鳟在7℃下暴露4周。在两个阶段，我们都测量了死亡率、体重、体长、组织中西酞普兰的浓度、暴露期间的行为以及在应激环境中的行为。对于褐鳟幼虫，还评估了孵化率和心率，对于幼年褐鳟，评估了组织皮质醇浓度。
在暴露期间，与对照鱼相比，暴露于最高测试浓度西酞普兰（1mg/L）的幼虫和幼鱼都有更高的游泳活动，并且在水族箱上部停留的时间更长，这是焦虑降低的一个指标。很可能是由于暴露期间游泳活动增加，暴露于1mg/L西酞普兰的幼鱼和幼虫体重和体长下降。此外，在一个应激的人工游泳测量装置中，褐鳟幼虫在这种应激情况下通过降低游泳活动表现出抗抑郁药的抗焦虑作用，在西酞普兰浓度为100μg/L时就已出现。组织化学分析显示，随着暴露浓度的增加，组织中西酞普兰的浓度升高。幼鱼的组织浓度比褐鳟幼虫高10倍。计算了鱼血浆浓度，最高暴露浓度超过了人类治疗水平，与行为结果相符。发育参数如孵化率和心率，以及死亡率和组织皮质醇含量不受抗抑郁药的影响。总体而言，我们能够追踪抗抑郁药西酞普兰在非目标生物褐鳟两个不同生命阶段的药理作用模式。
