昆虫味觉感受机制研究进展

Advances in mechanisms of taste perception in insects

很多昆虫具有极其灵敏的味觉感受系统,在其取食选择、交配和产卵等过程中起重要作用。相对于昆虫的嗅觉机制,对昆虫味觉感受机制的研究较少。传统的味觉感受研究主要集中在味觉感器外部形态、味觉电生理和行为学上。近年来随着分子遗传学、生物信息学和神经生物学技术的应用,昆虫味觉的研究不断深入,主要体现在下列两方面:(1)味觉受体方面,通过分子生物信息学等手段获得了多种昆虫的味觉受体,不同种昆虫之间受体数目差异较大,不同受体之间氨基酸的相似性较低。通常,根据味觉受体配体物质的性质可以把味觉受体分为取食抑制素受体和取食刺激素受体两大类。(2)味觉神经元的投射及味觉编码机制方面,多个研究表明昆虫外围味觉神经元在中枢神经系统中的投射部位为咽下神经节和后脑,但是不同性质的受体神经元投射的具体位置有所不同。本文对昆虫味觉感器和神经元的基本特征,味觉受体的进化、表达和功能,味觉神经元在中枢神经系统中的投射,味觉神经元的编码机制及味觉可塑性等进行了综述。

Many insects possess sensitive taste perception systems which play crucial roles in the processes of food selection, mating, and oviposition. The mechanism of taste perception is less studied compared to that of olfaction perception in insects. Most of the traditional taste studies are about the morphology and eleetrophysiology of gustatory sensilla, and behaviour. With the development of techniques on insect molecular genetics, bioinformatics and neurobiology in current years, taste perception mechanisms in insects have been better understood mainly in the following two aspects： （ 1 ）Insect gustatory receptor proteins （Grs） ： putative Grs of many insect species have been identified by bioinformatics, and the number and the protein sequences of Grs are extraordinarily divergent among different species of insects. In general, the Grs can be classified into phagostimulatory receptors and deterrent receptors based on the corresponding ligands. （2） Projections of gustatory sensory neurons on the central nervous system and neural coding mechanisms： projection of gustatory sensory neurons to different regions of the suboesophageal ganglion and the tritocerebrum of brain in insects has been investigated. This article reviews the research advances concerning basic characteristics of gustatory sensilla and gustatory sensory neurons, evolution, expression and function of Grs, projections of gustatory sensory neurons and plasticity of taste in insects.