Department of Zoology, Stockholm University, Svante Arrhenius väg 18B, S-106 91 Stockholm, Sweden.
J Exp Biol. 2010 Jul 1;213(Pt 13):2256-65. doi: 10.1242/jeb.043190.
The central complex is one of the most prominent neuropils in the insect brain. It has been implicated in the control of locomotor activity and is considered as a pre-motor center. Several neuropeptides are expressed in circuits of the central complex, and thus may be modulators of locomotor behavior. Here we have investigated the roles of two different neuropeptides, Drosophila tachykinin (DTK) and short neuropeptide F (sNPF), in aspects of locomotor behavior. In the Drosophila brain, DTK and sNPF are expressed in interneurons innervating the central complex. We have directed RNA interference (RNAi) towards DTK and sNPF specifically in different central complex neurons. We also expressed a temperature-sensitive dominant negative allele of the fly ortholog of dynamin called shibire(ts1), essential in membrane vesicle recycling and endocytosis, to disrupt synaptic transmission in central complex neurons. The spontaneous walking activity of the RNAi- or shibire(ts1)-expressing flies was quantified by video tracking. DTK-deficient flies displayed drastically increased center zone avoidance, suggesting that DTK is involved in the regulation of spatial orientation. In addition, DTK deficiency in other central complex neurons resulted in flies with an increased number of activity-rest bouts. Perturbations in the sNPF circuit indicated that this peptide is involved in the fine regulation of locomotor activity levels. Our findings suggest that the contribution of DTK and sNPF to locomotor behavior is circuit dependent and associated with particular neuronal substrates. Thus, peptidergic pathways in the central complex have specific roles in the fine tuning of locomotor activity of adult Drosophila.
中央复合器是昆虫脑中最显著的神经丛之一。它与运动活动的控制有关，被认为是运动前中心。几种神经肽在中央复合器的回路中表达，因此可能是运动行为的调节剂。在这里，我们研究了两种不同的神经肽，果蝇激肽（DTK）和短神经肽 F（sNPF）在运动行为方面的作用。在果蝇脑中，DTK 和 sNPF 表达在支配中央复合器的中间神经元中。我们针对不同的中央复合器神经元中的 DTK 和 sNPF 进行了 RNA 干扰（RNAi）。我们还表达了一种称为 shibire（ts1）的果蝇同源物 dynamin 的温度敏感显性负等位基因，该基因在膜囊泡回收和内吞作用中必不可少，以破坏中央复合器神经元中的突触传递。通过视频跟踪来量化 RNAi 或 shibire（ts1）表达的果蝇的自发行走活动。DTK 缺陷型果蝇表现出明显增加的中心区回避，表明 DTK 参与了空间定向的调节。此外，中央复合器中其他神经元中的 DTK 缺失导致活动休息的次数增加。sNPF 回路的干扰表明该肽参与了运动活动水平的精细调节。我们的发现表明，DTK 和 sNPF 对运动行为的贡献取决于回路，并与特定的神经元底物有关。因此，中央复合器中的肽能途径在成年果蝇运动活动的精细调节中具有特定的作用。
