The neuromuscular system in flatworms: serotonin and FMRFamide immunoreactivities, and musculature in Prodistomum alaskense (Digenea: Lepocreadiidae), an endemic fish parasite of the north-western Pacific

Using the immunocytochemical method and confocal scanning laser microscopy, the pioneering data are obtained on the muscle system organization and presence and localization of biogenic amine serotonin and FMRFamide-related peptides in the nervous system of trematode Prodistomum alaskense (Ward and Fillingham, 1934) Bray and Merrett, 1998 (family Lepocreadiidae). This flatworm is an intestinal parasite of endemic representatives of marine fauna of the north-western Pacific Ocean – the prowfish, Zaprora silenus Jordan, 1896 and the lumpfish, Aptocyclus ventricosus Pallas, 1769. The article provides data of scanning electron microscopy on the tegumental topography of P. alaskense. The body wall musculature of P. alaskense has three layers of muscle fibres – the outer circular, intermediate longitudinal and inner diagonal ones. The muscle system elements are well-developed in the attachment organs, digestive and reproductive systems, in the excretory sphincter. Serotonin- and FMRFamide-immunopositive neurons and neurites are found in the head ganglia, circular commissure, longitudinal nerve cords, and in the transversal connective commissures. The innervation of the oral and ventral suckers, pharynx, and the reproductive system compartments by the serotonergic and FMRFamide-immunopositive neurites is revealed. The results are discussed in connection with the published data on the presence and functional roles of the serotonin and FMRFamide-related peptides in Platyhelminthes.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author