Taurine is one of the most abundant amino acids in vertebrates involved in important physiological functions, including osmoregulation, membrane stability, and neuronal activity. The pleiotropic effects of taurine support the existence of different mechanisms of action (e.g., modulation of GABA_A, strychnine-sensitive glycine, and NMDA receptors), which can play a role in aggressive-related responses. However, the mechanisms underlying the effects of taurine on aggression are still poorly understood. Because aggression has been associated with diverse central mechanisms, especially serotonergic activity, we aimed to investigate the involvement of this system in taurine-induced aggression in zebrafish. We treated adult zebrafish with ρ-chlorophenylalanine (ρCPA), an inhibitor of the serotonin synthesis, as well as 5-HT_1A receptor antagonist and agonist (WAY100135 and buspirone, respectively). Taurine effects were tested individually at three concentrations (42, 150, and 400 mg/L) for 60 min. We further analyzed the effects on aggression and locomotion using the mirror-induced aggression test. Taurine concentration that changed behavioral responses was selected to the succeeding pharmacological experiments using ρCPA, WAY100135, and buspirone. We found that buspirone did not alter the aggression. Yet, 42 mg/L taurine increased aggression, which was abolished by ρCPA and WAY100135, indicating the involvement of 5-HT_1A receptors in taurine-mediated aggression. These set of data support an indirect mechanism mediating taurine-induced aggression via serotonin release and activation of 5-HT_1A receptors in zebrafish. While the exact mechanisms underlying aggression are still unclear, our novel findings reveal a key role of the serotonergic system in the effects of taurine, supporting the use of zebrafish models to understand the neural basis of aggression in vertebrates.

牛磺酸是脊椎动物中最丰富的氨基酸之一，参与重要的生理功能，包括渗透压调节，膜稳定性和神经元活性。牛磺酸的多效性作用支持存在不同的作用机制（例如，调节GABA _A，对士的宁敏感的甘氨酸和NMDA受体），它们可以在攻击性相关反应中发挥作用。然而，牛磺酸对侵略作用的潜在机制仍知之甚少。因为侵略与各种中心机制有关，尤其是血清素能活性，所以我们旨在研究该系统在牛磺酸引起的斑马鱼侵略中的作用。我们用5-氯苯丙氨酸（5-羟色胺合成抑制剂）和5-HT _1A处理成年斑马鱼受体拮抗剂和激动剂（分别为WAY100135和丁螺环酮）。在三种浓度（42、150和400 mg / L）下分别测试牛磺酸的作用60分钟。我们使用镜像诱发的攻击测试进一步分析了对攻击和运动的影响。使用ρCPA，WAY100135和丁螺环酮，根据随后的药理实验选择改变行为反应的牛磺酸浓度。我们发现丁螺环酮并没有改变侵略性。然而，42 mg / L牛磺酸增加了侵略性，被ρCPA和WAY100135废除了，表明5-HT _1A受体参与了牛磺酸介导的侵略。这些数据集支持间接机制，通过5-羟色胺释放和5-HT _1A激活介导牛磺酸诱导的侵略斑马鱼中的受体。虽然尚不清楚侵略的确切机制，但我们的新发现揭示了牛血清素能系统在牛磺酸作用中的关键作用，支持使用斑马鱼模型来理解脊椎动物侵略的神经基础。