异色瓢虫(Hanmonia axyridis)视叶中GABA阳性神经元的分布

Distribution of GABA-like immunoreactive neurons in the optic lobes of Hanmonia axyridis

目的 :探讨异色瓢虫视叶中γ 氨基丁酸 (GABA)能神经元的类型、形态特点、投射走向及分布规律。 方法 :树脂石蜡 (colophony paraffin ,CP ;专利号 :ZL9812 5 70 9.7)组织包埋切片技术结合免疫细胞化学链酶菌抗生物素蛋白 过氧化物酶 (streptavidin peroxidase ,SP)双染法。 结果 :GABA阳性纤维起源于大量细胞体 ,在视叶髓区具有广泛的分布 ,染色程度互不相同 ,并有分层现象 ,几条神经通路染色较浅 ;主要观察到 5种细胞类型 ,GABA能阳性细胞体染色显著 ,呈深褐色 ,根据其定位及神经突的走向可以区分为 8个细胞群。在本模型昆虫中还观察到视网膜后交叉和内髓板结构。结论 :GABA作为神经递质在传递视觉信息方面发挥重要的调节作用 ,且主要抑制局部神经活动 ,并在特定区域和 5 羟色胺 (5 HT)共同起作用。

Objective: To investigate the neuron types,morphic structure,projecting direction and distributing pattern of γ-aminobutyric acid (GABA)-ergic neurons in the optic lobes of Hanmonia axyridis. Methods: Colophony-Paraffin(CP,Patent number: ZL98125709.7) embedding tissue section technique combined with Streptavidin-Peroxidase (SP) immunocytochemical method was used. Results: The GABA immunoreactive fibers,which derived from a great number of cell bodies,had an extensive distribution in the neuropils of optic lobes. The three neuropils,the lamina,medulla and lobula complex varied from each other in the density of the staining and the pattern of the stratification. Three fiber tracts had been immunostained slightly. There were five catalogs of neuron types in the optic lobes. According to the location of the perikarya and the direction of the neurites,GABA-ergic neurons whose cell bodies demonstrated dark brown could be distinguished into eight groups. Post-retina chiasma and lobula plate also existed in Hanmonia axyridis .Conclusion: As a neurotransmitter,GABA plays an important role in processing visual inputs and mainly suppresses local neural activity. In some specific areas,GABA is colocalized and may serve as cotransmitters with serotonin (5-HT).