Serotonin and Neuropeptide FMRFamide in the Attachment Organs of Trematodes.

The serotoninergic and FMRFamidergic nervous system of the attachment organs of trematodes were examined using immunocytochemical techniques and confocal scanning laser microscopy. Adult trematodes from eight families as well as cercariae and metacercariae from ten families were studied. TRITC-conjugated phalloidin was used to stain the muscle fibres. The serotonin- and FMRFamide-immunoreactive (IR) nerve cells and fibres were revealed to be near the muscle fibres of the oral and ventral suckers of the trematodes and their larvae. The results indicate the important role of neurotransmitters, serotonin and neuropeptide FMRFamide in the regulation of muscle activity in the attachment organs of trematodes and can be considered in perspective for the development of new anthelmintic drugs, which can interrupt the function of the attachment organs of the parasites.

[Serotonin and neuropeptide FMRFamide in the nervous system of Opisthioglyphe ranae (Trematoda: Plagiorchiidae). an immunocytochemical study].

The presence and localization of the serotoninergic and FMRFamidergic structures in the nervous system of the trematode Opisthioglyphe ranae, the marsh frog intestinal parasite, was studied using immunocytochemistry. The serotonin-immunoreactive nerve cells and fibers were revealed in the head ganglia, circular commissure, longitudinal nerve cords and their connective commissures, as well as around the oral and ventral suckers, oesophagus and genital pore. FMRF-specific immunoreactivity was observed in the head ganglia, longitudinal nerve cords and terminal parts of the reproductive system. The results obtained are discussed in light of the available data on the presence and functional significance of the above-mentioned neurotransmitters in trematodes.

Neuromuscular system of the causative agent of dicrocoeliosis, Dicrocoelium lanceatum. I. 5-Hydroxytryptamine in the nervous system.

The trematode Dicrocoelium lanceatum known as lancet fluke, is a causative agent of dicrocoeliosis, a widespread parasitic disease of the grazing ruminants. The investigation of the major neurotransmitters and their functions are an important step in the development of a new pharmacological strategy of the struggle against the dicrocoeliosis affecting the neuronal signal substances and the functions of its nervous system. The aim of this work was to study the presence and localization of the neurotransmitter serotonin (5-HT, 5-Hydroxytryptamine) in the nervous system of D. lanceatum using immunocytochemical technique and confocal laser scanning microscopy. For the first time the data on the presence and distribution of serotonin-immunopositive components in the central and peripheral compartments of the nervous system of D. lanceatum has been obtained. Serotonin-immunopositive neurons and neurites were identified in paired brain ganglia, in the brain commissure, longitudinal nerve cords and connective nerve commissures. The innervation of the oral and ventral suckers by serotonergic nerve structures was revealed. The distal part of the reproductive system and the region of the reproductive pore were intensively innervated by serotonergic neurites. Serotonin-immunopositive neurons and neurites were also revealed in the proximal region of the reproductive system. The data obtained suggest that the serotonergic nervous system is involved in the regulation of the attachment organs and the reproductive system functions in D. lanceatum. The new results on the morphological and functional organization of the D. lanceatum nervous system increase our knowledge of the structure and function of nervous system of trematodes of various taxonomic groups and support the possibility of the exploitation of the serotonergic system of the parasite as a target for anthelmintic drugs.

[Formation of the photosensing system function in early development].

The function of simple prototypic eyes in two planarian species, the two ocular Girardia tigrina and the multiocular Polycelis tenuis, has been studied. When exposed to light, planarians display the light avoidance reaction known as negative phototaxis. This reaction has been investigated in intact animals and in head and tail fragments after their section in the course of eye regeneration. Specific features of the phototaxis reaction have been described in all groups of animals. The differences in light response recovery were shown between two planarian species and two regenerating fragments. No correlation between phototaxic reactions and the restoration of the eye structure, the number of eyes, the maturation of ganglion, the growth of regenerative blastema, and motor system has been found. The phototaxic response occurred two days after the recovery of the morphology of eyes and their connection with the brain. The participation of conserved and novel genes in early development of the eye function is discussed.

[Regeneration processes in various species of planarians].

Blastema growth and functional maturation of the pharynx during regeneration in various planarian species were compared. The intensity of blastema growth was highest in Polycelis tenuis; the lowest, in Schmidtea mediterranea. In the sexual and asexual races of Girardia tigrina blastema growth differed inconsiderably. The function of the pharynx during the regeneration of caudal fragments lacking pharynx was manifested in G. tigrina in the usual amount of time, while in the regeneration of head fragments lacking pharynx, this function occured earlier. In other planarian species of the other two typed, the times of pharynx regeneration had no regular character and took longer compared to the same process in G. tigrina.

The New Data on the Serotonin and FMRFamide Localization in the Nervous System of Opisthorchis felineus Metacercaria.

BACKGROUND: Trematoda Opisthorchis felineus Rivolta, 1884 is the causative agent of dangerous parasite disease-opisthorchiasis, widespread in the Russian Federation. The details of the neuroanatomical localization of the serotoninergic and FMRFamidergic neurotransmitter elements as well as their functional roles remain not studied enough in both adult and larval forms of O. felineus. The studies in this area are important in term of the development of a new pharmacological strategy of the struggle with the causative agent of opisthorchiasis affecting the neuronal signal substances and the function of its nervous system. PURPOSE: The aim of this work was the immunocytochemical study of the neurotransmitters serotonin (5-HT, 5-Hydroxitryptamine) and neuropeptide FMRFamide localization in the nervous system of the opisthorchiasis causative agent-O. felineus metacercaria. To study the relationship between the detected neurotransmitters and the muscular elements of the parasite, the muscle staining was carried out simultaneously using fluorophore-conjugated phalloidin. METHODS: The localization of 5-HTergic and FMRFamidergic nerve structures was determined by immunocytochemical method. The staining samples were analyzed using a fluorescent and confocal laser scanning microscopies. RESULTS: The new data on the presence and distribution of the serotonin-immunopositive (IP)- and FMRFa-IP components in the central and peripheral departments of the nervous system of  O. felineus metacercaria has been obtained. Besides that a number of the new anatomical details of the nervous system organization and of the innervation of the organs and tissues in the investigated parasite have been revealed. CONCLUSION: The data obtained on the presence and localization of the 5-HTergic and peptidergic (FMRFamide) components in central and peripheral departments of the nervous system of O. felineus metacercaria elaborated and expanded the existing information about the nervous system as well as the innervations of the tissues and organs in the causative agent of opistchorchiasis.

[Effects of weak physical and chemical factors on morphogenetic processes in invertebrates].

Numerous data of long-term investigations of weak agents on morphogenetic processes in invertebrates (regeneration of planarians, Dugesia (Girardia) tigrina and postembryonic development of insects, the grain beetle Tenebrio molitor) have been analyzed. Weak physical and chemical factors were used: electromagnetic radiation, static, alternating, and combined magnetic fields, and low concentrations of solutions of neuropeptides. Some common features of the influence of weak factors on morphogenesis were found, namely, the instability and the opposite direction of the effect. The dependence of the effects on external conditions and the dynamics of physiological functions of objects was established.

[Pharynx regeneration in planarians].

The obtained and published data on pharynx regeneration in planarians have been reviewed. Planarians can regenerate from a small body fragment and restore all missing organs including the pharynx. The pharynx is a relatively autonomous organ with a differentiated structure and specialized function. Pharynx regeneration has specific features, and its studies are of considerable theoretical interest. Pharynx regeneration can also be a convenient model to study the molecular mechanisms of regeneration that remain undisclosed. In addition, this model can be used to test biologically active compounds in order to elucidate their effect on morphogenesis. This subject of investigation benefits by a simpler and more adequate analysis as well as a possibility to use large numbers of animals and small quantities of analyzed substances.

[Influence of weak electromagnetic field on different forms of behavior in grain beetle, Tenebrio molitor].

The influence of weak electromagnetic radiation on simple forms of behavior was studied on the model of the motor behavior of the imago grain beetle (Tenebrio molitor). Positive (feeding) and negative (illumination) motivations were created in the same experimental conditions. Beetles in a Petri dish were put to the starting point of a special container. The goal (a peace of potato or a box protected from light) was in the other fixed point of the container. Time of the goal reaching by groups of beetles was recorded in one daily trial in the course of five consecutive days. Under conditions of both motivations, behavioral phases such as orienting reaction and environmental adaptation were observed. Exposure to weak electromagnetic radiation resulted in an increase in the reaction time at the initial stage of the experiment. The effect was of a seasonal character and varied depending on the behavioral form.

[Resources of regeneration in planarians].

We studied the intensity of blastema growth in operated planarians at an early stage of regeneration as a function of the following factors: area of regenerate and its function and number of regeneration foci (volume of regeneration). There was no direct dependence between the intensity of regeneration and the size of regenerating fragment, as well as the volume of regeneration. Some specific features of the early stage of regeneration have been described, which suggest its determinate character. The behavior of neoblasts during formation of blastemas with different localization is discussed.

[Asexual reproduction of planarians: metric studies].

A relationship was studied between fission and restoration of body and its individual parts under different experimental conditions in planarians of the Dugesia tigrina asexual race. The body and its fragments were studied morphomterically. After fission, the growth of planarians demonstrated topographic differences. The separated tail fragments and postpharyngeal area, in which the zone of fission is formed, were growing at the highest rate. More active growth was also noted over the long body axis. Fission and growth were more active in isolated planarians, as compared to those kept in groups.

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).

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.

Neuropeptides in flatworms.

The use of well-characterized antibodies raised to neuronal signal substances and their application through immunocytochemistry and confocal scanning laser microscopy has revolutionized studies of the flatworm nervous system (NS). Data about flatworm neuropeptides and the spatial relationship between neuropeptides and other neuronal signal substances and muscle fibers are presented. Neuropeptides form a large part of the flatworm NS. Neuropeptides are especially important as myoexcitatory transmitters or modulators, controlling the musculature of the attachment organs, the stomatogastric and the reproductive systems.

[Effect of weak electromagnetic radiation on regeneration of the pharynx in Dugesia tigrina planaria]. / Issledovanie vliianiia slabogo élektromagnitnogo izlucheniia na regeneratsiiu glotki u planarii Dugesia tigrina.

We have studied the effect of weak electromagnetic field on the morphogenesis of the planarian Dugesia tigrina. Regeneration of the pharynx was examined after its amputation. We have determined the rate of the appearance of the food response of a new pharynx. Experimental conditions were varied, such as dose and duration of irradiation, season, and time of irradiation after surgery. The results of experiments conducted with 2966 planarians have shown that weak electromagnetic field has various effects, which appear either as stimulation of regeneration or as its inhibition. In some experiments, there was no effect at all. These differences depend on numerous factors and may be modulated.

[Morphogenesis in planarians Dugesia tigrina]. / Morfogenez u planarii Dugesia tigrina.

We carried out computer morphometry in regenerates of planarians Dugesia tigrina. The blastema growth was analyzed in fragments of planarians after their fission and after transverse transection at different body levels. The blastema was growing at a higher rate on tail fragments than on the head fragments and the growth rate was the higher, the closer the transection was to the head end. After fission, the blastema was growing at a slower rate than after transection in the fission zone. The growth of adjacent blastemas formed on both sides after fission or transection proceeded at different rates as a function of new body polarity.

Effects of weak electromagnetic irradiation on various types of behavior in the mealworm Tenebrio molitor.

The effects of weak electromagnetic irradiation on simple forms of behavior were studied using adult Tenebrio molitor mealworms. The beetles' motor behavior was studied in conditions of different motivations, i.e., positive (food) and negative (avoidance of light), in otherwise identical experimental conditions. The beetles had to navigate a defined space to reach their target - potato or cover from light. Experiments consisted of one trial per day for five days. Target attainment time was measured in groups of beetles. Behavior in both cases developed as follows: an initial orientation reaction appeared and was followed by adaptation to the apparatus. Exposure to weak electromagnetic irradiation led to increases in the response time at the initial stages of the experiments. The effects of irradiation were seasonal in nature and differed in the two types of behavior.

Combined treatment with vitamin B12b and ascorbic acid causes in vitro DNA degradation in tumor cells.

Incubation of Ehrlich ascites carcinoma and HEp-2 human epidermoid laryngeal carcinoma cells with hydroxycobalamin (vitamin B12b) and ascorbic acid induced generation and accumulation of double-stranded DNA fragments (23,000 b.p. and longer) in cells. The same vitamins alone in the same concentrations produced no such effects. DNA degradation in HEp-2 cells caused by long-term (4 h) incubation with 5-25 microM hydroxycobalamin and ascorbic acid (1:10-1:40 molar ratio) at 37 degrees C was comparable with that induced by gamma-irradiation in a dose of 150 Gy at 4 degrees C.