Electron immunogold labeling of regulatory peptide immunoreactivity in the nervous system ofMoniezia expansa (Cestoda: Cyclophyllidea)
An electron immunogold-labeling technique was used in conjunction with a post-embedding procedure to demonstrate for the first time the ultrastructural distribution of the parasitic platyhelminth neuropeptide, neuropeptide F (NPF(, in the nervous system of the cestodeMoniezia expansa. Two axon types, distinguished by their populations of different-sized electron-dense vesicles, were identified. Immunogold labeling demonstrated an apparent homogeneity of PP, FMR Famide and NPF (M. expansa) antigenic sites throughout the larger dense-cored vesicles within the central nervous system. Triple labeling clearly demonstrated the co-localisation of immunoreactivities (IR) for NPF, PP and FMR Famide within the same dense-cored vesicles. The presence of NPF-IR within the vesicles occupying the perikaryon of the neuronal cell body indicated that the peptides had undergone post-translational C-terminal amidation prior to entering the axon. Antigen pre-absorption experiments using NPF prevented labeling with either PP or FMR famide antisera, and the failure of these antisera to block NPF-IR supports the view that some, if not all, of the PP/FMR Famide-IR is due to NPF-like peptides.
KeywordsPeptide Neuronal Cell Cell Body Regulatory Peptide Neuronal Cell Body
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