Abstract：
The dynamic properties of neural systems throughout life can be hijacked by so-called manipulative parasites. This study investigated changes in the brain chemistry of the amphipod Gammarus fossarum in response to infection with two trophically-transmitted helminth parasites known to induce distinct behavioral alterations: the bird acanthocephalan Polymorphus minutus and the fish acanthocephalan Pomphorhynchus tereticollis. We quantified brain antioxidant capacity as a common marker of homeostasis and neuroprotection, and brain total protein, on 72 pools of six brains. We analyzed the concentration of serotonin (5HT), dopamine (DA) and tyramine in 52 pools of six brains, by using ultrafast high performance liquid chromatography with electrochemical detection (UHPLC-ECD). Brain total protein concentration scaled hypo-allometrically to dry body weight, and was increased in infected gammarids compared to uninfected ones. The brain of gammarids infected with P. minutus had significantly lower total antioxidant capacity relative to total proteins. Infection with P. tereticollis impacted DA level compared to uninfected ones, and in opposite direction between spring and summer. Brain 5HT level was higher in summer compared to spring independently of infection status, and was decreased by infection after correcting for brain total protein concentration estimated from dry whole-body weight. The potential implication of 5HT/DA balance in parasite manipulation, as a major modulator of the reward-punishment axis, is discussed. Taken together, these findings highlight the need to consider both brain homeostatic and/or structural changes (antioxidant and total protein content) together with neurotransmission balance and flexibility, in studies investigating the impact of parasites on brain and behavior.
摘要：
整个生命中神经系统的动态特性可能被所谓的操纵性寄生虫劫持。这项研究调查了两栖动物Gammarusfossarum的大脑化学变化，以响应两种已知的滋养传播的蠕虫寄生虫的感染，这些寄生虫会引起明显的行为改变：微小的鸟类棘头虫和鱼类棘头虫Pomphorhynchusterticollis。我们将大脑抗氧化能力量化为稳态和神经保护的常见标志，和大脑总蛋白，在72个由六个大脑组成的池子上。我们分析了血清素（5HT）的浓度，多巴胺（DA）和酪胺在52个6个大脑池，采用超快高效液相色谱电化学检测(UHPLC-ECD)。大脑总蛋白浓度与干体重呈低异速变化，与未感染的gammarids相比，感染的gammarids增加了。与总蛋白质相比，感染小P的gammarids的大脑总抗氧化能力显着降低。与未感染的相比，感染有对DA水平的影响。春天和夏天之间的方向相反。与感染状态无关，夏季大脑5HT水平高于春季。并且在校正了从干体重估计的大脑总蛋白浓度后，由于感染而降低。5HT/DA平衡在寄生虫操纵中的潜在意义，作为奖罚轴的主要调制器，正在讨论。一起来看,这些发现强调需要考虑大脑稳态和/或结构变化（抗氧化剂和总蛋白质含量）以及神经传递平衡和灵活性，在调查寄生虫对大脑和行为的影响的研究中。
