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Biomedical subjects

G A Buznikov

Publications and source records attributed to G A Buznikov.

At least 37 records · Page 2Linked to original sources
PubMed1984

Effect of calcium ionophore A23187 on the sensitivity of early sea urchin embryos to cytotoxic neuropharmacological drugs.

The ability of cytotoxic neurochemicals (indole and amphetamine derivatives) to block first cleavage division in the embryos of the sea urchin Arbacia lixula abruptly increases when the embryos are incubated in calcium-free seawater and decreases when the external Ca concentration is raised up to 46.4 mM. Sensitivity of the embryos to these drugs decreases also in the presence of the Ca-ionophore A23187. It is suggested that Ca ions are involved in the realization of physiological effects of "prenervous" neurotransmitters whose presence in early sea urchin embryos was shown by us earlier.

Amphetamines↗
PubMed1984

[Effect of cyclic nucleotides on the sensitivity of early sea urchin embryos to cytotoxic neuropharmacological preparations].

It has been shown that cytotoxic action of neuropharmacological drugs (transmitter antagonists) on early urchin embryos is reduced or abolished by cyclic nucleotides and sodium fluoride. Such a protective action differs in cAMP and dibutyryl analogs of cyclic nucleotides, depending on the chemical structure of an embryotoxic substance. It is suggested that, endogenous intracellular "prenervous" transmitters and cyclic nucleotides are interrelated in the regulation of cell division in urchin embryos.

Animals↗
PubMed1981

Possible role of "prenervous" neurotransmitters in cellular interactions of early embryogenesis: a hypothesis.

Evidence is presented in support of the working hypothesis that "prenervous" neurotransmitters directly participate in cell-cell interactions occurring during the first several cleavage divisions of sea urchin embryos, a function which may occur during the early development of higher animals as well. This intercellular signaling could be a link in the evolutionary progression from the use of these substances as intracellular regulators to their participation in cell-cell interactions occurring during synaptic transmission.

Animals↗
PubMed1981

Immunochemical study of gangliosides at the cell surface of sea urchin embryos.

Two main gangliosides (G-1 and G-2) were isolated from eggs and embryos S. intermedius. They contain glucose, N-glucolylneuraminic acids, phytosphyngosine, fatty acids and alpha-hydroxy fatty acids. Molar ratios and sequence of these components are the same for both gangliosides, but G-2 contains sulphate residue which is attached to the terminal neuraminic acid. To obtain specific antisera rabbits were immunized by G-1 or G-2, which were mixed with bovine serum albumin and Freund's adjuvant. Both gangliosides possessed electrophoretic and antigenic heterogeneity. G-1 and G-2 gangliosides have common and individual antigenic determinants. Glucosylceramide of gangliosides is immunologically inactive. Individual antigenic specificity of the gangliosides depends on the presence of N-glycolylneuraminic acid (G-1) and SO3H-group (G-2). Egg gangliosides were demonstrated by immunofluorescence throughout the cell surface. After fertilization of immunofluorescent label was concentrated on one pole of the embryo only. During the development of specific fluorescence was again uniformly distributed at the blastomer surface. The most intense fluorescence was observed in the junction areas of the blastomers.

Animals↗
PubMed1981

Biogenic monoamines in early embryos of sea urchins.

Indolylalkylamine determination was performed on the eggs and embryos of six species of sea urchins, using several fluorometric techniques, including the fluorescence of a substance itself and the fluorescence of its condensation products after treatment with orthophthaldialdehyde and ninhydrin. The serotonin-like substance of sea urchin embryos as well as of adults was shown to consist of at least two components, of which the major one is tryptamine or its derivative with a substituting group at aminonitrogen. Further, serotonin was found to be present at all developmental stages investigated. although at much lower concentrations. The results of this study suggest a regulatory role of 'prenervous' tryptamine in the early embryogenesis of the sea urchin.

Animals↗
PubMed1979

[Sensitivity of fragmented and stratified sea urchin embryos to cytotoxic neuropharmacological preparations].

The red half embryos and related quarter embryos (yolk and pigment) of Arbacia lixula, obtained by means of centrifugation of the eggs in sucrose gradient, retain the normal level of sensitivity and supersensitivity to cytotoxic neuropharmaca, antagonists of biogenic monoamines. The white half embryos and clear quarter embryos practically lack supersensitivity whereas the granular quarter embryos restore it to the initial level. The non-pigmented blastomers of stratified embryos are characterized by somewhat weakened supersensitivity. A suggestion is put forward that the supersensitive embryos of A. lixula possess a sensibilizing factor which couples the supersensitivity receptors with the processes of cell division and moves together with the yolk granules upon centrifugation. This factor is not observed in the Strongylocentrotus granularis embryos lacking evident supersensitivity.

Amphetamines↗
PubMed1978

[Effect of antimediator preparations on the intercellular relations in early embryos of the sea urchin].

The dated treatment of the early embryos of an irregular (flat) sea urchin Scaphechinus mirabilis by neuropharmacological drugs (anti-neurotransmitters) during one of the first four cleavage divisions results in the impairment of intercellular connections and leads to the formation of twin embryos, dwarf embryos, embryos of the dumb-bell shape etc. In the experiments with some of the drugs under study such developmental abnormalities were not seen or were expressed much more weakly when serotonin or bufotenin (N,N-dimethylserotonin) were added to the medium. A suggestion is put forward that the early embryos possess an intracellular mechanism participating in the interaction between the cells and operating via endogenous monoamines, primarily serotonin.

Animals↗
PubMed1978

[Relationship between the ganglioside composition of Ehrlich ascitic carcinoma and cell population density].

The ganglioside composition of Ehrlich ascite carcinoma cells changes drastically with changes in density of the cell population. Upon 30-fold dilution of the native cell suspension and subsequent incubation for 2 h the amount of total gangliosides per cell doubles the quantities of a monosialoganglioside and of a disialoganglioside increase ten- and five-fold, respectively, whereas the other cell gangliosides do not change. The decrease of cell density is supposed to be accompanied by induction on the cell surface of a sialytransferase activity, which appears to be depressed in the dense suspension.

Animals↗
PubMed1975

Effect of antimycin A on sensivitivy of fertilized sea urchin egg cells to embryotoxic analogs of serotonin.

Antimycin A blocks cleavage divisions in concentrations 1-10-15-1-10-14 g/ml (experiments on Arbacia lixula) or 1-10-11-1-10-9 g/ml (experiments on sea urchins of the genus Strongylocentrotus). Subthreshold and threshold concentrations of this antibiotic do not affect the sensitivity of fertilized Strongylocentrotus intermedius to 1-benzyl-2, 5-dimethylserotonin, but increase their sensitivity to 5-butyltryptamine by a factor of 3-5. These data provide the basis for a discussion of the possible nature of the reception of serotonin and other low-molecular-weight regulators of early embryogenesis.

Animals↗