昆虫气味认知的嗅觉神经结构及分子机制

摘要

大多数昆虫主要通过气味认知感知外界环境的变化,维持生命活动.探究昆虫气味认知的嗅觉系统神经结构及分子机制,对于完善气味认知神经生物学理论及利用其原理进行仿生学研究等有重要的科学意义.近年,关于昆虫气味认知科学研究有了很大的进展.本文从昆虫神经生物学的视角详细综述了近年关于昆虫气味认知的嗅觉神经结构、分子机制及气味信号的神经传导途径等方面的基本理论及最新研究成果.综述结果显示:昆虫对气味的认知是通过嗅觉神经系统的触角感器、触角叶(AL)、蕈形体(MB)等脑内多层信号处理神经结构来实现的.当外界气味分子进入触角感器内后,由感器内特定的气味识别蛋白(OBP)将气味分子运载到达嗅觉感受神经元(ORN)树突膜上的受体位点,气味分子与表达特定气味的受体(OR)结合产生电信号,并以动作电位的形式通过ORN的轴突传到脑内的触角叶.在触角叶经过嗅觉纤维球对气味信息选择性加工处理,再由投射神经元(PNs)将初步的识别和分类的气味信息传到蕈形体和外侧角(LH)等神经中枢,实现对气味的识别和认知.虽然,近年昆虫气味认知神经生物学的研究有了很大的进步,但是,我们认为目前的研究成果还不能完全阐明昆虫气味认知的神经机制,还有很多问题,例如,触角叶上众多的嗅觉纤维球是如何对嗅觉感受神经元传入的气味信息进行编码处理的？等有待进一步深入研究.为了搞清这些疑难问题,我们认为需要提高现有的实验技术水平,加强电生理学和分子神经生物学相结合的实验研究,从分子水平探究气味认知的神经机制可能是未来研究的热点.%Most insects mainly perceive external environment throught ordor,to maintain life activities.Research on the olfactory neuromechanism and molecular mechanism is important to make clear the function of insect olfactory cognitive and the bionics research by neural mechanisms of insect ordor perception.In recent years,the technology of neurobiology and molecular biology have great progress,especially the research on olfactory neuralstructure and molecular mechanism of insect odor perception,which makes a deeper research on the insect olfactory neural loop and molecular.According to the latest research results,this review focuses on the insect olfactory neuralstructure,molecular mechanism and the odor signal pathway including antennal sensilla,antennal lobe and mushroom body,as well as molecular mechanism of ordor perception and olfactory singnal pathway.Review results:Insect cognition of smell is realized through the olfactory nerve system in the brain nerve structure of multilayer signal processing,including antennal sensilla,antennal lob,and mushroom body.When the external odor molecules into the antennal sensilla,the sense of odour recognition protein specific device to odor molecules carrying reach the olfactory receptor neurons dendritic membrane receptor,odor molecules combination with the specific odor receptor produces electrical signal,with the action potentials through the ORN axon to the AL.In the antennal lobe after olfactory glomeruli has selective processing of olfactory information,then the PNs drlivery identification and classification odor information to MB and LH of the central nervous system,to achieve recognition and perception of odor.Although,recent studies of insect odorant cognitive neuroscience has made great progress,we believe that the results of the present study is not completely clarified the neural mechanisms of odorant perception.There are a lot of problems,such as,how lots of the olfactory glomeruli of antennal lobe encode the odor information introduction by the olfactory receptor.We need further study.In order to clarify these problems,we need to improve the existing experimental techniques,strengthening the electrophysiology and molecular neurobiology combination,neural mechanism of odor recognition from the molecular level may be the focus of study in the future.