肝片形吸虫神经系统内5-羟色胺的定位和色胺能神经元超微结构的研究

LOCALIZATION OF SEROTONIN AND ULTRASTRUCTURE OF SEROTONERGIC NEURONS IN THE NERVOUS SYSTEM OF Fasciola hepatica

用间接免疫荧光技术鉴定了肝片形吸虫神经系统内5-羟色胺(5-HT)的定位。在中枢,脑神经节内胞体、突起、连合和发出的纵神经干均呈现免疫反应;在外周,皮肌层、肠管壁、睾丸和卵巢上皮周围、子宫和卵模肌内层等的神经丛也有免疫反应。用电镜技术进一步研究色胺能神经元的超微结构,发现其胞体集中于神经节,其终末纤维有经典的突触结构,内含5-HT颗粒.因此,5-HT作为肝片形吸虫的神经递质有了直接证据。

Rabbits antisera were raised against an antigen prepared by coupling 5-HT to bovine serum albumin (BSA) using formaldehyde as a coupling reagent.The fresh adult Fasciola hepatica were fixed with 4% formaldehyde and sectioned on a cryostat.The sections were stained by indirect immunofluorescence technique.Abundant immunofluorescence specific for 5-HT was observed in ganglion cell bodies and their processes,the transverse commis-.sure that connects two ganglia and longitudinal axes extending from the ganglia.Immunore-activity to 5-HT was also found in'the nerve fibre innervating tegument,gut wall,the epithelium of testes or ovary,the musculature of uterus and ootype,etc.The ultrastructure of serotonergic neurons was visualized.As in other invertebrates,the serotonergic neurons of Fasciola hepatica consisted of cell bodies,axons,synapses,herring bodies and neuromuscu-lar junctions.The nerve cell bodies were aggregatively located in ganglia and many dispersed spherical granular vesicles were present in cytoplasm.The nerve axons branched out to the muscles forming synapses,where synaptic vesicles contained 5-HT dense-core granules were found.The distribution of 5-HT within the neurons strongly suggested that 5-HT was functioning as a neurotrasmitter in Fasciola hepatica.