Morphological and Functional Characteristics of the Trematode Fasciola hepatica Musculature

The morphological structure and functional properties of musculature of flatworms Fasciola hepatica (Trematoda, Fasciolidae), parasites dangerous for agricultural animals and humans, have been studied. The histochemical staining of the body wall muscles of F. hepatica with fluorescently-labelled phalloidin has been performed and the stained samples were examined by fluorescent microscopy. Staining was observed both in longitudinal, circular, and diagonal muscle fibers of the body wall of the trematode, in the circular and diagonal muscle fibers surrounding the lumens of the branched intestine, and in the tubular structures of the reproductive tract. In the ventral and oral suckers of the trematode, tightly packed and intensively stained layers of muscle fibers were found. The physiological studies were conducted on the muscle strips prepared from F. hepatica. The results demonstrated that muscle preparations exhibit spontaneous contractile activity. Neuropeptide GYIRF, belonging to the FMRFamide-like peptide family, used at concentrations ranging from 1 µm to 10 µm, additionally stimulated the contractions of muscle preparations in F. hepatica, increasing the frequency and amplitude of contractions compared to their basic activity. The information obtained will be used in further investigation of muscle contraction mechanism in parasitic worms, the muscles of which are targets of antiparasitic drugs.