蚊虫嗅觉识别的神经机制

蚊虫主要依赖嗅觉系统与外界环境进行化学信息交流。蚊虫通过嗅觉感受系统寻找食物、 配偶和产卵场所， 进而做出相应的行为反应。本文综述了近年来蚊虫嗅觉系统对气味信号神经传导机制的研究进展。蚊虫的嗅觉感器主要位于触角和下颚须， 触角上的毛形感器和锥形感器感受氨水、 乳酸、 羧酸类化合物等人体和其他动物释放的微量气味物质， 下颚须上的锥形感器则感受呼出的二氧化碳以及一些其他的挥发性物质； 蚊虫嗅觉感器内部有受体神经细胞， 其上分布有嗅觉受体蛋白， 蚊虫对外界环境的化学感受就是通过气味物质与这些受体蛋白互作而得以实现； 根据对不同气味物质的反应谱差异， 嗅觉神经细胞被分为不同的功能类型； 来自嗅觉神经细胞的神经信号进一步从外周传导至中枢神经中脑触角叶内的神经小球， 在此对信息进行初步的处理， 通过评估嗅觉神经细胞的反应和触角叶内的神经小球相应被激活的区域， 不同小球被分别命名； 最后， 神经信号继续整合， 由投射神经传向前脑， 最终引发一系列昆虫行为反应。这些研究从理论上剖析了气味信号在蚊虫嗅觉系统中的神经转导通路， 对于我们深刻理解蚊虫的嗅觉系统具有重要意义， 同时也有助于进一步理解其他昆虫甚至人类的气味识别机制及进行更深层次神经科学的探索。

Neuron mechanism of olfactory perception in mosquitoes

 Mosquitoes are highly dependent on their olfactory system for chemical communication with the external environment including searching for foods, mating partners and oviposition sites. This article reviews the research progress on neuron projection mechanism of olfactory system to odor signals in mosquitoes. Olfactory appendages in moquitoes include antennae and maxillary palps that carry a variety of sensilla. Sensilla trichodea and sensilla grooved-peg in the antennae are sensitive to ammonia, L-lactic acid and carboxylic acids. The grooved peg sensilla in the maxillary palp are sensitive to carbon dioxide. These sensilla house olfactory receptor neurons (ORNs) in which olfactory receptor proteins are embedded. Host detection in mosquitoes starts with interactions between odorants and receptor proteins present on the dendritic membrane of the ORNs. ORNs are divided into different functional classes based on the response spectra to different odours. ORNs project to different glomerular areas of the antennal lobe (AL) in the deuterocerebrum of the central nervous system. The antennal lobe glomeruli in different response area are identified. The neuron signal is finally transduced to projection neuron (PN) in the potocerebrum and elicits the behaviour response of mosquitoes. These researches shed light on the neuron transduction channel of odor signal in olfactory system in mosquitoes. These results are very important for us to understand not only olfactory system in mosquitoes but also the odor perception mechanism of other insect species and human, and are helpful for further exploration in neuron science.