Sex differences in aggression: Differential roles of 5-HT2, neuropeptide F and tachykinin
Sex differences in aggression: Differential roles of 5-HT2, neuropeptide F and tachykinin
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DOI：
10.1371/journal.pone.0203980
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发表时间：
2019-01-29
期刊：
影响因子：
3.7
通讯作者：
Swallow, John G.
中科院分区：
文献类型：
--
作者：
Bubak, Andrew N.;Watt, Michael J.;Swallow, John G.
尽管在获取食物和配偶等关键资源方面，跨类群的攻击行为具有保守的功能，但血清素（5-HT）对攻击行为的调节作用似乎对脊椎动物主要是抑制性的，但对无脊椎动物是刺激性的。然而，在明确阐述 5-HT 和攻击性的对立作用之前，我们对无脊椎动物的了解存在重大差距，需要解决这些问题。具体来说，5-HT 受体亚型的作用很大程度上是未知的，5-HT 与其他已知在攻击行为中发挥关键作用的神经化学系统的潜在相互作用作用也是未知的。同样，这些系统对无脊椎动物攻击行为性别差异的影响尚不清楚。在这里，我们通过在一种新型无脊椎动物攻击模型——茎眼蝇——中采用补充方法来研究这些问题。社会条件改变、药理操作和 siRNA 敲除 5-HT2 受体的结合揭示了该受体亚型对攻击行为的抑制作用。此外，我们提供了 5-HT2 参与调节神经肽 F 活性的证据，神经肽 F 是一种可疑的攻击性抑制剂。然而，该功能似乎是特定于阶段的，仅改变攻击性冲突的起始阶段。或者，从药理学上增加 5-HT 的全身浓度可显着提高神经肽速激肽的表达，这不会影响竞赛的开始，而是通过产生高强度的攻击行为来促进升级。值得注意的是，这些影响仅限于男性，而女性的攻击性和神经肽表达并未因任何影响 5-HT 的操作而改变。总之，这些结果表明 5-HT 在调节无脊椎动物攻击性方面具有更微妙的作用，揭示了与神经肽的重要相互作用作用，这更让人想起脊椎动物。这里描述的性别差异也为了解这种复杂行为的进化背景提供了宝贵的见解。
Despite the conserved function of aggression across taxa in obtaining critical resources such as food and mates, serotonin's (5-HT) modulatory role on aggressive behavior appears to be largely inhibitory for vertebrates but stimulatory for invertebrates. However, critical gaps exist in our knowledge of invertebrates that need to be addressed before definitively stating opposing roles for 5-HT and aggression. Specifically, the role of 5-HT receptor subtypes are largely unknown, as is the potential interactive role of 5-HT with other neurochemical systems known to play a critical role in aggression. Similarly, the influence of these systems in driving sex differences in aggressive behavior of invertebrates is not well understood. Here, we investigated these questions by employing complementary approaches in a novel invertebrate model of aggression, the stalk-eyed fly. A combination of altered social conditions, pharmacological manipulation and 5-HT2 receptor knockdown by siRNA revealed an inhibitory role of this receptor subtype on aggression. Additionally, we provide evidence for 5-HT2's involvement in regulating neuropeptide F activity, a suspected inhibitor of aggression. However, this function appears to be stage-specific, altering only the initiation stage of aggressive conflicts. Alternatively, pharmacologically increasing systemic concentrations of 5-HT significantly elevated the expression of the neuropeptide tachykinin, which did not affect contest initiation but instead promoted escalation via production of high intensity aggressive behaviors. Notably, these effects were limited solely to males, with female aggression and neuropeptide expression remaining unaltered by any manipulation that affected 5-HT. Together, these results demonstrate a more nuanced role for 5-HT in modulating aggression in invertebrates, revealing an important interactive role with neuropeptides that is more reminiscent of vertebrates. The sex-differences described here also provide valuable insight into the evolutionary contexts of this complex behavior.