CELLULAR AND SUBCELLULAR-LOCALIZATION OF SALMFAMIDE (S1)-LIKE IMMUNOREACTIVITY WITHIN THE CENTRAL-NERVOUS-SYSTEM OF THE NEMATODE ASCARIS-SUUM (NEMATODA, ASCAROIDEA)

The localization and distribution of SALMFamide (S1)-like immunoreacti vity (IR), was determined at both the cellular and subcellular level i n the central nervous system (CNS) of the nematode roundworm Ascaris s uum. The techniques of indirect immunofluorescence in conjunction with confocal scanning laser microscopy and post-embedding, IgG-conjugated colloidal gold immunostaining were used, respectively. Immunostaining was widespread in the CNS of adult A. suum, with immunoreactivity (IR ) being localized in nerve cells and fibres in the ganglia associated with the anterior nerve ring and in the main nerve cords and their com missures. At the subcellular level, gold labeling of peptide was local ized exclusively over dense-cored vesicles within nerve cell bodies, n erve axons and nerve terminals of the neuropile of the anterior nerve ring, main ganglia and nerve cords in the CNS. Double-labeling demonst rated an apparent co-localization of S1- and FMRFamide-IR-together IR- together with S1- and pancreatic polypeptide (PP)-IR in the same dense -cored vesicles. Antigen preabsorption experiments indicated little cr oss-reactivity, if any, between the three antisera; indeed, neither FM RFamide nor PP antigens abolished S1 immunostaining.