Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Rm 4020C, Mississauga, ON, L5L 1C6, Canada.
Amino Acids. 2012 Nov;43(5):2059-72. doi: 10.1007/s00726-012-1284-0. Epub 2012 Apr 11.
Zebrafish form shoals in nature and in the laboratory. The sight of conspecifics has been found reinforcing in zebrafish learning tasks. However, the mechanisms of shoaling, and those of its reinforcing properties, are not known. The dopaminergic system has been implicated in reward among other functions and it is also engaged by drugs of abuse as shown in a variety of vertebrates including zebrafish. The ontogenetic changes in dopamine levels and, to a lesser degree, in serotonin levels, have been found to accompany the maturation of shoaling in zebrafish. Thus, we hypothesized that the dopaminergic system may contribute to shoaling in zebrafish. To test this we employed a D1-receptor antagonist and quantified behavioral responses of our subjects using a social preference (shoaling) paradigm. We found significant reduction of social preference induced by the D1-R antagonist, SCH23390, in the AB strain of zebrafish, an alteration that was not accompanied by changes in motor function or vision. We also detected D1-R antagonist-induced changes in the level of dopamine, DOPAC, serotonin and 5HIAA, respectively, in the brain of AB zebrafish as quantified by HPLC with electrochemical detection. We found the antagonist-induced behavioral changes to be absent and the levels of these neurochemicals to be lower in another zebrafish population, SF, demonstrating naturally occurring genetic variability in these traits. We conclude that this variability may be utilized to unravel the mechanisms of social behavior in zebrafish, a line of research that may be extended to other vertebrates including our own species.
斑马鱼在自然和实验室中形成鱼群。研究发现，同类的存在可以增强斑马鱼的学习能力。然而，鱼群形成的机制及其增强特性尚不清楚。多巴胺能系统在奖励等功能中起作用，也被包括斑马鱼在内的各种脊椎动物的滥用药物所激活。多巴胺水平的发育变化，以及在较小程度上的 5-羟色胺水平的发育变化，伴随着斑马鱼鱼群的成熟。因此，我们假设多巴胺能系统可能有助于斑马鱼的鱼群形成。为了验证这一点，我们使用了 D1 受体拮抗剂，并使用社会偏好（鱼群）范式对我们的研究对象的行为反应进行了量化。我们发现 D1-R 拮抗剂 SCH23390 显著降低了 AB 品系斑马鱼的社会偏好，这种改变没有伴随着运动功能或视觉的改变。我们还通过 HPLC-ECD 检测发现，AB 品系斑马鱼大脑中的多巴胺、DOPAC、5-羟色胺和 5HIAA 水平分别发生了 D1-R 拮抗剂诱导的变化。我们发现拮抗剂引起的行为变化在另一个斑马鱼种群 SF 中不存在，这些神经化学物质的水平也较低，这表明这些性状存在自然发生的遗传变异性。我们得出结论，这种变异性可用于揭示斑马鱼社会行为的机制，这一研究方向可以扩展到包括人类在内的其他脊椎动物。
