title: Comparative study of the spatial relationship between nicotinamide adenine dinucleotide phosphate-diaphorase activity, serotonin immunoreactivity, and GYIRFamide immunoreactivity and the musculature of the adult liver fluke, Fasciola hepatica (Digenea, fasciolidae).
abstract: This is the first detailed description of the nitrergic nervous system in a fluke. In this study, the authors analysed the distribution of the nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) reactivity in neuronal and nonneuronal tissues of the adult fluke Fasciola hepatica and compared this with the distribution of the musculature using tetramethylrhodamine isothiocyanate-phalloidin. To assess the correlation between the number of muscle cells in different parts of the fluke and the NADPH-d-stained cells, the nuclei were stained with Hoechst 333 42, which is specific for chromatin. The spatial relation between the NADPH-d-positive nerves and the 5-hydroxytryptamine (serotonin; 5-HT)-immunoreactive (-IR) and GYIRFamide-IR nervous elements was also examined. The methods complement each other. NADPH-d-positive staining occurs in both in neuronal tissue and nonneuronal tissue. Large, NADPH-d-stained neurones were localised in the nervous system. The oral and ventral suckers are innervated with many large NADPH-d-stained neurones. In addition, the NADPH-d staining reaction follows closely the muscle fibres in both the suckers, in the body, and in the ducts of the reproductive organs. The presence of NADPH-d activity along muscle fibres in F. hepatica and in other flatworms supports a possible myoinhibitory role for nitric oxide. Neuronal nitric oxide synthase in flatworms may form a novel drug target, which would facilitate the development of a novel anthelminthic.
authors.affiliation: Department of Biology, Abo Akademi University, FIN-20520 Abo, Finland. magustaf@abo.fi
authors.forename: M K
authors.initials: MK
authors.lastname: Gustafsson
authors.forename: N B
authors.initials: NB
authors.lastname: Terenina
authors.forename: N D
authors.initials: ND
authors.lastname: Kreshchenko
authors.forename: M
authors.initials: M
authors.lastname: Reuter
authors.forename: A G
authors.initials: AG
authors.lastname: Maule
authors.forename: D W
authors.initials: DW
authors.lastname: Halton
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000166:cytology / Q000378:metabolism*; D005210:Fasciola hepatica / Q000166:cytology* / Q000378:metabolism*; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000378:metabolism; D005835:Genitalia / Q000166:cytology / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D009412:Nerve Fibers / Q000378:metabolism / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism*; D010614:Pharynx / Q000166:cytology / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*
chemical_list: D009479:Neuropeptides; D009842:Oligopeptides; C105067:glycyl-tyrosyl-isoleucyl-arginyl-phenylalaninamide; D012701:Serotonin; D009252:NADPH Dehydrogenase