《环境昆虫学报》

桔小实蝇Bactrocera dorsalis是一种对农业造成严重威胁的害虫，尤其是其幼虫阶段对作物的取食危害最为显著，导致农作物产量下降。5-羟色胺（5-HT）作为一种重要的神经递质，调节了昆虫的取食等多种行为。因此，探究桔小实蝇幼虫脑内5-羟色胺能神经元网络的功能，能够为明确其具体行为调节机制及开发针对该靶标的行为调节剂提供基础。本研究采用突触蛋白和5-羟色胺抗体进行桔小实蝇3龄幼虫神经系统的免疫组织化学染色，并利用激光共聚焦显微镜观察获取幼虫神经系统的结构特征及5-羟色胺能神经元的分布模式。结果表明，桔小实蝇幼虫的中枢神经系统主要由脑和胸腹神经节构成，且两者相互融合，整体神经系统呈左右对称排列。研究发现，脑内各神经髓发育不完全，颚神经节和胸神经节均包含3个神经原节，而腹神经节包含8个，且各神经原节间的分界清晰。3龄幼虫脑内共含86个5-羟色胺能神经元，其中中央脑含20个，颚神经节含22个，胸腹神经节含44个。中央脑的20个细胞体可进一步划分为4个细胞体簇，每簇含1~3个细胞体。此外，在脑内发现6条神经连合连接两侧脑半球。颚神经节内的SE2和SE3细胞体簇投射出神经突起形成神经连合。5-羟色胺能神经元呈对称排列在胸腹神经节两侧，并向外投射神经突起形成神经连合。本研究揭示了桔小实蝇幼虫神经系统中5-羟色胺能神经元的分布特征，为理解该生物胺对其行为调控提供了解剖学结构基础，并为理解该生物胺能神经元在双翅目昆虫中的发育及组装方式提供参考。

英文摘要:

The oriental fruit fly (Bactrocera dorsalis) is a serious agricultural pest, particularly during its larval stage, when it poses significant threats to crops and leads to reduced agricultural yields. Serotonin (5-HT), an important neurotransmitter, regulates various behaviors in insects, including feeding. Therefore, investigating the serotonergic neural network in the brains of B. dorsalis larvae is crucial for clarifying the specific mechanisms underlying behavioral regulation and for developing behavioral modulators targeting this pathway. In this study, we performed immunohistochemical staining of the nervous system of third-instar B. dorsalis larvae using synapsin and serotonin antibodies, followed by analysis of the structural features and distribution patterns of serotonergic neurons using laser confocal microscopy. Our results indicated that the central nervous system of B. dorsalis larvae primarily consists of the brain and thoraco-abdominal ganglia, which were interconnected and exhibit a bilateral symmetrical arrangement. We found that the neuropils in the brain were underdeveloped, with the gnathal ganglion and thoracic ganglia each containing 3 neuromeres, while the abdominal ganglion comprises eight, with distinct boundaries between each neuromere. A total of 86 serotonergic neurons were identified in the brain of third-instar larvae, including 20 in the central brain, 22 in the gnathal ganglion, and 44 in the thoraco-abdominal ganglia. The 20 cell bodies in the central brain can be further classified into four clusters, each containing 1 to 3 cell bodies. Additionally, six commissures connecting the two brain hemispheres were observed. The SE2 and SE3 cell body clusters in the gnathal ganglion project neurites to form commissures. The serotonergic neurons were symmetrically arranged on both sides of the thoraco-abdominal ganglia, extending neurites outward to form additional commissures. This research reveals the distribution characteristics of serotonergic neurons in the nervous system of B. dorsalis larvae, providing an anatomical foundation for understanding how this biogenic amine regulates behavior. It also offers insights into the development and assembly of serotonergic neurons in dipteran insects.

查看全文查看/发表评论下载PDF阅读器

关闭