Sublethal exposures to environmental pollutants may cause changes in physiological parameters. Thus, knowledge of basal physiological rates of the species and the development of methods to quantify these rates are extremely important. Considering the scarcity of cardiac and muscle physiological studies in native Amazonian fish species and that no evaluation of electrophysiological responses by exposure to a stressor has been reported in Bryconops caudomaculatus, the aim of this study was to develop techniques of electromyographic and electrocardiographic recordings of normal responses, during toxicity induction and short-term recovery. A total of 9 animals were used, divided into two groups: control group (n = 4) and treated group (n = 5), with records lasting 5 min. The results showed that the basal electromyographic records indicate that the studied species has a very intense swimming activity, whereas the basal cardiac parameters clearly showed the patterns in P wave tracing, QRS complex, T wave and Q-T and R-R intervals. During exposure to the stressor, muscle activity ceased presenting intense decrease and myorelaxant effect expected. Electrocardiographic responses confirmed cardiotoxicity with intense bradycardia, ventricular bigeminism, prolongation of QRS complex duration and cardiac arrhythmias, indicating cardiac dysfunction. It was concluded that the electrophysiological responses are excellent biomarkers and showed the susceptibility of the species to the tested substance. In addition, the electrocardiogram and the electromyogram are excellent techniques to reflect the degree of environmental stress when organisms are exposed to toxic substances in the environment.

中文翻译：

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亚马逊鱼类Bryconops caudomaculatus（Osteichthyes：Characiformes）的电生理响应，作为异种生物毒性的生物标记。

亚致死性暴露于环境污染物中可能会导致生理参数发生变化。因此，了解该物种的基础生理速率以及开发量化这些速率的方法非常重要。考虑到本地亚马逊鱼类缺乏心脏和肌肉生理学研究，并且在Bryconops caudomaculatus中没有通过暴露于应激源对电生理反应进行评估的报道，该研究的目的是开发正常反应的肌电图和心电图记录技术，在毒性诱导和短期恢复期间。总共使用9只动物，分为两组：对照组（n = 4）和治疗组（n = 5），记录持续5分钟。结果表明，基础肌电图记录表明所研究的物种具有非常强烈的游泳活动，而基础心脏参数清楚地显示了P波示踪，QRS波群，T波以及QT和RR间隔的模式。在暴露于应激源的过程中，肌肉活动停止呈现强烈的下降，并且预期会出现肌肉松弛现象。心电图反应证实了心脏毒性，包括强烈的心动过缓，心室肥大症，QRS持续时间延长和心律不齐，表明心脏功能障碍。结论是，电生理反应是优良的生物标志物，并显示出该物质对被测物质的敏感性。此外，