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V Margotta

Publications and source records attributed to V Margotta.

At least 37 records · Page 2Linked to original sources
PubMed1986

Preliminary histochemical and electron microscopic observations on the nervous system of hydra.

The nervous system of a primitive Coelenterate (Chlorohydra viridissima) has been studied using ultrastructural and histochemical techniques. The authors confirm the ultrastructural pattern of nerve cells described by Lentz and coworkers. Reserpine treatment fails to induce any reduction of catechol- and indoleamine content visible to histochemical observation. In vivo treatment with tetanus toxin does not induce behavioural changes and no specific binding of toxin is revealed by immunocytological analysis. This suggests that neuron tetanus toxin receptor sites are absent in hydra. Hydra nerve cells must therefore be considered as extremely primitive elements, which the Authors consider to support the hypothesis of neurons having originated as a gradual differentiation of myoepithelial cells, as proposed by Pantin (1956) and by Passano (1963).

Animals↗
PubMed1984

Aminergic neurotransmitters and adenylate cyclase in hydra.

Serotonin, dopamine and, in lesser amounts, norepinephrine were detected in Chlorohydra viridissima with electrochemical detection coupled to liquid chromatography (LCED). Treatment with reserpine induces a significant decrease in amine levels. Adenylate cyclase was found in Hydra tissue; the enzyme is stimulated by Mg, Mn and F and sensitive to guanine nucleotide activation. Dopamine, serotonin, GSH and glutamate do not affect cyclase activity.

Adenylyl Cyclases↗
PubMed1983

Radioimmunological and immunocytochemical demonstration of Met-enkephalin in planaria.

1. An anti-Met-enkephalin serum has been used for radioimmunological and immunocyto-chemical demonstration of Met-enkephalin in planaria. 2. The serum showed a high degree of sensitivity and specificity. 3. Radioimmunoassay demonstrated in planaria extracts a considerable concentration of Met-enkephalin. 4. Met-enkephalin was localized by immunocytochemical methods in neurons and neuropil.

Animals↗
PubMed1983

The cerebrum of Dugesia gonocephala s.1. Platyhelminthes, Turbellaria, Tricladida. Morphological and functional observations.

Investigation of the cerebrum of Dugesia gonocephala s.1. using modern techniques has shown that the neurons of these animals situated at the bottom of the phylogenetic scale are basically the same as those of Vertebrates from the ultrastructural and molecular standpoints (tetanus toxin binding). There is no evidence of any biochemical glio-neuronal relationship, nor do the so-called supporting cells appear similar to the glial cells of the higher Vertebrates from this point of view.

Animals↗
PubMed1981

Photosensitization and the nervous system in the planarian Dugesia gonocephala. A histochemical, ultrastructural and behavioral investigation.

Photosensitization phenomena may be induced in planarias by eosin and hematoporphyrin, and as a result, dopamine agonistic behavior ("screw-like hyperkinesia") is set up in the animal. Histochemical, ultrastructural and pharmacological investigations have shown that this hyperkinesia is of post-synaptic origin in eosin photosensitization, and of pre-synaptic origin in hematoporphyrin photosensitization. The authors suggest an hypothesis to explain the different activity of the two photosensitizers, and discuss the validity of the experiment with regard to human porphyria.

Animals↗
PubMed1979

The pigmentary system of planaria. I. Morphology.

The pigmentary system of the planaria, Dugesia gonocephala s.l. (Platyhelminthes, Turbellaria, Tricladida), has been studied by light and electron microscopy. The system consists of granules contained in chromatophore-like cells embedded in the parenchyma. The cell processes penetrate between the muscle layers and extend to the sub-epidermal basal lamina. The nature of the pigment and the comparative anatomical significance of the chromatophore structure is discussed.

Animals↗
PubMed1979

The pigmentary system of planaria. II. Physiology and functional morphology.

The pigmentary system of the planaria, Dugesia gonocephala s.l. (Platyhelminthes, Turbellaria, Tricladida), consists of granules contained in chromatophore cells distributed in the parenchyma tissue. The administration of MSH release-inhibiting Factor (M.I.F.) leads to an easily observable general decolouration of the animal due to the migration of the pigment granules towards the deeper-lying cell nucleus. In planarians bisected transversely through the pharyngeal region, the decolouration occurs only in the cephalic segment, and the caudal segment remains dark. When, however, the decapitated caudal segment regenerates a head region, a decolouration response occurs when exposed to M.I.F. The significance of these results is discussed, and an hypothesis on the hormonal regulation of the pigmentary system is proposed.

Animals↗
PubMed1975

Proposal of a new model with dopaminergic-cholinergic interactions for neuropharmacological investigations.

The motor system of Dugesia gonocephala shows a striking similarity with the extrapyramidal system of high vertebrates and of man with the evidence of correlations between dopaminergic and cholinergic neurons. The utilization of this model seems to be useful in testing drugs which presumably act on dopaminergic or cholinergic transmission. In this model, the quantification of animal behaviour seems considerably easier when compared with the difficulties met in other animal models commonly employed. Besides, it might be anticipated that this model, if correctly used, can display interesting perspectives also in neuroendocrinological investigations.

Acetylcholine↗