Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States of America.
Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States of America.
PLoS One. 2018 Jun 27;13(6):e0198362. doi: 10.1371/journal.pone.0198362. eCollection 2018.
Octopamine regulates feeding behavioral responses in Drosophila melanogaster, however the molecular and circuit mechanisms have not been fully elucidated. Here, we investigated the role of a subset of octopaminergic neurons, the OA-VPM4 cluster, in sucrose acceptance behavior. Thermogenetic activation of Gal4 lines containing OA-VPM4 promoted proboscis extension to sucrose, while optogenetic inactivation reduced extension. Anatomically, the presynaptic terminals of OA-VPM4 are in close proximity to the axons of sugar-responsive gustatory sensory neurons. Moreover, RNAi knockdown of a specific class of octopamine receptor, OAMB, selectively in sugar-sensing gustatory neurons decreased the behavioral response to sucrose. By calcium imaging experiments, we found that application of octopamine potentiates sensory responses to sucrose in satiated flies. Taken together, these findings suggest a model by which OA-VPM4 promotes feeding behavior by modulating the activity of sensory neurons.
章鱼胺调节果蝇的摄食行为反应，但分子和电路机制尚未完全阐明。在这里，我们研究了一组章鱼胺能神经元，即 OA-VPM4 簇，在蔗糖接受行为中的作用。Gal4 线包含 OA-VPM4 的热激活促进了对蔗糖的伸喙，而光激活抑制了延伸。在解剖学上，OA-VPM4 的突触前末端与对糖有反应的味觉感觉神经元的轴突密切相邻。此外，特异性在糖感觉味觉神经元中敲低特定类别的章鱼胺受体 OAMB，选择性地降低了对蔗糖的行为反应。通过钙成像实验，我们发现章鱼胺的应用增强了饱食果蝇对蔗糖的感觉反应。综上所述，这些发现表明 OA-VPM4 通过调节感觉神经元的活性来促进摄食行为的模型。
