Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
Proc Natl Acad Sci U S A. 2017 Nov 14;114(46):E9962-E9971. doi: 10.1073/pnas.1712706114. Epub 2017 Oct 31.
In , the sex pheromone produced by males, -vaccenyl acetate (cVA), evokes a stereotypic gender-specific behavior in both males and females. As adults feed, mate, and oviposit on food, they perceive the pheromone as a blend against a background of food odors. Previous studies have reported that food odors enhance flies' behavioral response to cVA, specifically in virgin females. However, how and where the different olfactory inputs interact has so far remained unknown. In this study, we elucidated the neuronal mechanism underlying the response at an anatomical, functional, and behavioral level. Our data show that in virgin females cVA and the complex food odor vinegar evoke a synergistic response in the cVA-responsive glomerulus DA1. This synergism, however, does not appear at the input level of the glomerulus, but is restricted to the projection neuron level only. Notably, it is abolished by a mutation in gap junctions in projection neurons and is found to be mediated by electrical synapses between excitatory local interneurons and projection neurons. As a behavioral consequence, we demonstrate that virgin females in the presence of vinegar become receptive more rapidly to courting males, while male courtship is not affected. Altogether, our results suggest that lateral excitation via gap junctions modulates odor tuning in the antennal lobe and drives synergistic interactions between two ecologically relevant odors, representing food and sex.
在昆虫中，雄性产生的性信息素 - 顺-3-十二烯乙酸酯（cVA）在雌雄两性中均能引起刻板的性别特异性行为。当成年果蝇进食、交配和产卵时，它们将信息素与食物气味的混合物感知为一种信号。先前的研究报告称，食物气味增强了苍蝇对 cVA 的行为反应，特别是对处女雌蝇。然而，不同嗅觉输入是如何以及在何处相互作用的，目前仍不清楚。在这项研究中，我们从解剖学、功能和行为水平阐明了对该反应的神经机制。我们的数据表明，在处女雌蝇中，cVA 和复杂的食物气味醋会在 cVA 反应性肾小球 DA1 中引起协同反应。然而，这种协同作用似乎不是在肾小球的输入水平上发生的，而是仅局限于投射神经元水平。值得注意的是，这种协同作用在投射神经元中的缝隙连接突变中被消除，并被发现是由兴奋性局部中间神经元和投射神经元之间的电突触介导的。作为一种行为后果，我们证明，在有醋的情况下，处女雌蝇对求爱雄蝇的接受速度更快，而雄蝇的求爱行为不受影响。总的来说，我们的结果表明，通过缝隙连接的侧向外展调节了触角叶中的气味调谐，并驱动了两种具有生态相关性的气味（食物和性）之间的协同相互作用。
