Morphological and Functional Characteristics of the Trematode Fasciola hepatica Musculature

The morphological structure and functional properties of musculature in a flatworm Fasciola hepatica (Trematoda, Fasciolidae), a dangerous parasite of farm animals and humans, have been studied. The flatworm body musculature was stained histochemically with fluorescently labeled phalloidin and analyzed using fluorescence microscopy. The presence of staining was found in the longitudinal, circular, and diagonal muscle fibers of the worm’s body wall, as well as in the circular and diagonal muscle fibers surrounding the lumens of the branched intestine, as well as in the tubular muscle structures of the reproductive tract. Densely packed and intensely stained layers of muscle fibers were found in the ventral and oral suckers of the flatworm. Physiological studies conducted on muscle preparations isolated from F. hepatica, demonstrated the presence of spontaneous contractile activity of the muscles. The neuropeptide GYIRF, from the family of FMRFamide-like peptides, at concentrations of 1–10 µM, additionally stimulated the contraction of muscle preparations of F. hepatica, increasing the frequency and amplitude of muscle contractions compared with their basic activity. The information obtained will be used in further study of the mechanisms of muscle contraction in parasitic worms, whose musculature is the target of existing antiparasitic drugs.