桔小实蝇视叶结构特征及5-羟色胺能神经元的分布

Structural characteristics of optic lobe and distribution of 5-HT immunoreactive neurons in the oriental fruit fly

桔小实蝇是重要的果蔬害虫,它对不同颜色的光表现出不同的趋性。为了明确其视觉感受的结构基础,本研究采用免疫组织化学染色技术结合激光共聚焦成像分析了桔小实蝇成虫视叶内神经髓结构组成和体积大小,并利用5-羟色胺(5-hydroxytryptamine,5-HT)抗体标记了视叶内5-羟色胺能神经元,研究了其在视叶内的分布特征及细胞体数量。结果表明,桔小实蝇成虫的视叶由视神经节层、视髓、副视髓、视小叶和视小叶板5个神经髓结构组成,其中雌成虫的视髓相对体积极显著的大于雄虫的视髓相对体积。桔小实蝇每个视叶中包含12个5-HT能神经元细胞体,位于视髓的腹内侧,副视髓的前方。视叶5个神经髓区均含5-HT能神经纤维,但它们的神经纤维来自不同的神经元。对视叶神经髓结构及5-HT能神经元分布特征的研究将为未来构建桔小实蝇视觉神经通路和阐明5-HT对视觉感受的调控机制奠定解剖学基础。

The oriental fruit fly Bactrocera dorsalis Hendel is an important pest of fruits and vegetables, it shows a different tendency to the light of different colors. In order to clarify the structural basis of visual perception, the structure and volume of optic lobes in adult flies were analyzed by immunohistochemical staining combined with laser confocal imaging. The serotoninergic neurons in the optic lobe were labeled with 5-HT antibody, and the distribution characteristics and the number of somata in the optic lobes were studied. The results showed that the optic lobes of adults flies were composed of the lamina, medulla, accessory medulla, lobula,and lobula plate. The relative volume of the medulla of the female was significantly larger than that of the male adults. Each optic lobe contains 12 5-HT immunoreactivity cell bodies, which mainly distribute in the ventromedial part of the medulla and anterior of the accessory medulla. All five neuropils in the optic lobe contain 5-HT immunoreactivity neural processes, but they innervated by different neurons. The study on the structure of the neuropils in the optic lobe and the distribution of 5-HT immunoreactivity neurons will lay the anatomical foundation for constructing the visual neural pathway and clarifying the mechanism of the regulation of serotonin on the visual perception of oriental fruit fly in the future.