Cellular, Molecular and Microbial Biology Graduate Program, University of Montana, Missoula, Montana, United States of America.
Division of Biological Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, United States of America.
PLoS Genet. 2020 Feb 25;16(2):e1008609. doi: 10.1371/journal.pgen.1008609. eCollection 2020 Feb.
Neuromodulators such as monoamines are often expressed in neurons that also release at least one fast-acting neurotransmitter. The release of a combination of transmitters provides both "classical" and "modulatory" signals that could produce diverse and/or complementary effects in associated circuits. Here, we establish that the majority of Drosophila octopamine (OA) neurons are also glutamatergic and identify the individual contributions of each neurotransmitter on sex-specific behaviors. Males without OA display low levels of aggression and high levels of inter-male courtship. Males deficient for dVGLUT solely in OA-glutamate neurons (OGNs) also exhibit a reduction in aggression, but without a concurrent increase in inter-male courtship. Within OGNs, a portion of VMAT and dVGLUT puncta differ in localization suggesting spatial differences in OA signaling. Our findings establish a previously undetermined role for dVGLUT in OA neurons and suggests that glutamate uncouples aggression from OA-dependent courtship-related behavior. These results indicate that dual neurotransmission can increase the efficacy of individual neurotransmitters while maintaining unique functions within a multi-functional social behavior neuronal network.
神经调质（如单胺类）通常在至少释放一种快速作用神经递质的神经元中表达。递质的组合释放提供了“经典”和“调制”信号，这些信号可能在相关回路中产生多样化和/或互补的效应。在这里，我们确定大多数果蝇章鱼胺（OA）神经元也是谷氨酸能的，并确定了每种神经递质对性别特定行为的个体贡献。没有 OA 的雄性表现出低水平的攻击性和高水平的同性求爱。仅在 OA-谷氨酸神经元（OGN）中缺乏 dVGLUT 的雄性也表现出攻击性降低，但同性求爱没有同时增加。在 OGN 内，一部分 VMAT 和 dVGLUT 斑点在定位上存在差异，表明 OA 信号存在空间差异。我们的发现确立了 dVGLUT 在 OA 神经元中的先前未确定作用，并表明谷氨酸使攻击性与 OA 依赖性与求爱相关的行为脱钩。这些结果表明，双重神经传递可以提高单个神经递质的功效，同时在多功能社会行为神经网络中保持独特的功能。
