Schmidel Ademir J, Assmann Karla L, Werlang Chariane C, Bertoncello Kanandra T, Francescon Francini, Rambo Cassiano L, Beltrame Gabriela M, Calegari Daiane, Batista Cibele B, Blaser Rachel E, Roman Júnior Walter A, Conterato Greicy M M, Piato Angelo L, Zanatta Leila, Magro Jacir Dal, Rosemberg Denis B
Programa de Pós-graduação em Ciências Ambientais, Área de Ciências Naturais e Exatas, Universidade Comunitária da Região de Chapecó, Avenida Senador Attílio Fontana, 591E, 89809-000 Chapecó, SC, Brazil.
Programa de Pós-graduação em Zoologia, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Avenida Ipiranga, 6681, 90619-900, Porto Alegre, RS, Brazil.
Neurotoxicol Teratol. 2014 Jul-Aug;44:62-9. doi: 10.1016/j.ntt.2014.05.006. Epub 2014 Jun 2.
Animal behaviour is the interaction between environment and an individual organism, which also can be influenced by its neighbours. Variations in environmental conditions, as those caused by contaminants, may lead to neurochemical impairments altering the pattern of the behavioural repertoire of the species. Atrazine (ATZ) is an herbicide widely used in agriculture that is frequently detected in surface water, affecting non-target species. The zebrafish is a valuable model organism to assess behavioural and neurochemical effects of different contaminants since it presents a robust behavioural repertoire and also all major neurotransmitter systems described for mammalian species. The goal of this study was to evaluate the effects of subchronic ATZ exposure in defensive behaviours of zebrafish (shoaling, thigmotaxis, and depth preference) using the split depth tank. Furthermore, to investigate a putative role of cholinergic signalling on ATZ-mediated effects, we tested whether this herbicide alters acetylcholinesterase (AChE) activity in brain and muscle preparations. Fish were exposed to ATZ for 14days and the following groups were tested: control (0.2% acetone) and ATZ (10 and 1000μg/L). The behaviour of four animals in the same tank was recorded for 6min and biological samples were prepared. Our results showed that 1000μg/L ATZ significantly increased the inter-fish distance, as well as the nearest and farthest neighbour distances. This group also presented an increase in the shoal area with decreased social interaction. No significant differences were detected for the number of animals in the shallow area, latency to enter the shallow and time spent in shallow and deep areas of the apparatus, but the ATZ 1000 group spent significantly more time near the walls. Although ATZ did not affect muscular AChE, it significantly reduced AChE activity in brain. Exposure to 10μg/L ATZ did not affect behaviour or AChE activity. These data suggest that ATZ impairs defensive behaviours of zebrafish, which could be related to its action on brain cholinergic neurotransmission. Moreover, the use of the split depth tank could be an alternative strategy to assess group behaviour and depth preference after exposure to chemical compounds.
动物行为是环境与个体有机体之间的相互作用，这种相互作用也可能受到其邻体的影响。环境条件的变化，如由污染物引起的变化，可能导致神经化学损伤，从而改变物种行为模式。阿特拉津（ATZ）是一种广泛用于农业的除草剂，经常在地表水中被检测到，会影响非目标物种。斑马鱼是一种有价值的模式生物，可用于评估不同污染物的行为和神经化学效应，因为它具有丰富的行为模式，并且拥有哺乳动物物种所描述的所有主要神经递质系统。本研究的目的是使用分隔深度水槽评估亚慢性ATZ暴露对斑马鱼防御行为（群居、趋触性和深度偏好）的影响。此外，为了研究胆碱能信号在ATZ介导的效应中的假定作用，我们测试了这种除草剂是否会改变脑和肌肉制剂中的乙酰胆碱酯酶（AChE）活性。将鱼暴露于ATZ 14天，并对以下组进行测试：对照组（0.2%丙酮）和ATZ组（10和1000μg/L）。记录同一水槽中四只动物的行为6分钟，并制备生物样品。我们的结果表明，1000μg/L的ATZ显著增加了鱼之间的距离，以及最近和最远邻体的距离。该组还表现出群居区域增加，社交互动减少。在浅水区的动物数量、进入浅水区的潜伏期以及在装置浅水区和深水区花费的时间方面未检测到显著差异，但1000μg/L ATZ组在壁附近花费的时间明显更多。虽然ATZ不影响肌肉中的AChE，但它显著降低了脑中的AChE活性。暴露于10μg/L的ATZ对行为或AChE活性没有影响。这些数据表明，ATZ损害斑马鱼的防御行为，这可能与其对脑胆碱能神经传递的作用有关。此外，使用分隔深度水槽可能是评估接触化学化合物后群体行为和深度偏好的一种替代策略。
