INCIA - Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux, CNRS UMR 5287, 146 Rue Leo Saignat, 33076 Bordeaux, France.
Sci Rep. 2017 Jan 3;7:39935. doi: 10.1038/srep39935.
Social interactions leading to dominance hierarchies often elicit psychological disorders in mammals including harassment and anxiety. Here, we demonstrate that this sequence also occurs in an invertebrate, the crayfish Procambarus clarkii. When placed in the restricted space of an aquarium, crayfish dyads generally fight until one of the opponents suddenly escapes, thereafter clearly expressing a submissive behaviour. Nevertheless, the winner frequently keeps on displaying excessive aggressive acts, having deleterious consequences in losers and interpreted as harassment behaviour. We indeed observed that, contrary to winners, losers expressed anxiety-like behaviour (ALB) in correlation with the stress intensity they suffered during the harassment period mainly. Injections of an anxiolytic abolished ALB, confirming its homology with anxiety. A serotonin (5-HT) antagonist had the same effect, suggesting a role for 5-HT, whose brain concentrations increased much more in losers than in winners. Our findings suggest that the bases of harassment and of its anxiogenic consequences have emerged very early during evolution, and emphasize crayfish as an unexpected but potentially fruitful model for the study of these social disorders.
导致支配等级的社会互动常常在哺乳动物中引发心理障碍，包括骚扰和焦虑。在这里，我们证明这种序列也发生在无脊椎动物，淡水小龙虾 Procambarus clarkii 中。当将小龙虾放在水族箱的受限空间中时，它们通常会互相争斗，直到其中一个对手突然逃跑，此后，逃跑的一方会明显表现出顺从的行为。然而，胜利者经常会继续表现出过度的攻击行为，这对失败者造成了有害的后果，可以被解释为骚扰行为。我们确实观察到，与胜利者相反，失败者表现出类似焦虑的行为（ALB），这与它们在骚扰期间所经历的压力强度有关。注射抗焦虑药物可消除 ALB，证实其与焦虑具有同源性。5-羟色胺（5-HT）拮抗剂有相同的效果，表明 5-HT 起作用，其在失败者大脑中的浓度比胜利者高得多。我们的发现表明，骚扰及其焦虑后果的基础在进化过程中很早就出现了，并强调了小龙虾作为研究这些社会障碍的一个意外但有潜在价值的模型。
