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Biomedical subjects

E I Solntseva

Publications and source records attributed to E I Solntseva.

At least 37 records · Page 2Linked to original sources
PubMed1988

[Abolition of the inhibitory effect of antibodies against S-100 proteins on the calcium current of molluscan neurons after intracellular injection of EGTA].

A two-electrode voltage clamp method was used to study Ca inward current (ICa) in unidentified isolated snail neurons. Extracellular administration of antibodies against S-100 proteins (AS-100) produces a reversible inhibition of ICa in a dose-dependent and time-dependent manner. Intracellular injection of EGTA with the help of 10nA 5-10 min microiontophoresis through a multibarrel microelectrode evoked a weak increase in the amplitude of the ICa before AS-100 application and a complete abolition of the inhibitory effect of AS-100 on the ICa. The data obtained suggest that AS-100 application results in an increase in the intracellular Ca concentration and Ca-dependent inactivation of Ca-channels.

Animals↗
PubMed1987

[Effect of quinine on the calcium currents of mollusk neurons].

The effects of quinine on the peak amplitude and relaxation of calcium current (ICa) were examined on isolated unidentified snail neurons. Quinine (1 X 10(-5)-5 X 10(-4) mol/l) reversibly slowed the relaxation of ICa in a dose-dependent manner (early effect) and suppressed the peak amplitude of ICa in a dose-dependent and time-dependent manner (delayed effect). Quinine induced a shift of the current-voltage relationship for peak ICa by 5-10 mV in the hyperpolarizing direction. A half inhibition of ICa peak amplitude was induced by 6 X 10(-5) mol/l quinine. The results show that quinine is an effective inhibitor of calcium channels in snail neurons.

Animals↗
PubMed1987

[Mechanisms of the stimulating effect of brain antibodies on the Ca2 current in the neuron membrane].

Antibodies against rat brain microsomes induce a 16 +/- 3% increase in the amplitude of Ca-current (ICa) in snail neurons. Ca-ions block ICa in dose-dependent and potential-dependent manner. Antibodies against microsomes decrease the effectiveness of ICa blockade by Ca-ions: a 85 +/- 10% increase in ICa is observed and I-V curve is normalized. It is suggested that an enhancing effect of antibodies on ICa and the elimination of blocking Ca-effect on ICa are connected with the weakening of divalent cations binding by the anionic groups of calcium channels.

Animals↗
PubMed1987

[The role of cAMP in generating excitatory serotonin responses of neurons in the edible snail].

The neurons of the dorsal surface of snail Helix subesophageal ganglia respond similarly to the application of serotonin and the intracellular cAMP injection. These responses represent membrane depolarization. They increase in amplitude with membrane hyperpolarization and have a reverse potential between +10 and -30 mV. Presumably, these responses are associated with increased conductance for several ions. The values of the reverse potentials of serotonin and cAMP responses coincide in 7 out of 17 cells. Phosphodiesterase inhibitor theophylline caused a reversible increase in the amplitude and duration of both serotonin and cAMP responses and, used at a concentration of 1 mM, simulated them. The results obtained meet 2 out of 4 criteria demonstrating that cyclic nucleotides mediate a neurotransmitter response. It is suggested that cAMP may act as a second messenger in excitatory serotonin responses of snail Helix neurons.

Animals↗
PubMed1985

[Dynamic changes in the response of molluscan neurons to cyclic AMP with repeated injections].

Microiontophoretic injection of cAMP (but not of non-cyclic AMP) into Helix snail neurons induces rapid reversible membrane depolarization. The reversa potential of the cAMP response varies between +10 and -30 mV in different cells. The amplitude of the responses gradually increases (15 experiments), decreases (4 experiments) or remains unchanged (40 experiments) when the interval between the injections is less than 5 minutes. The identified neurons of the different preparations exhibit different types of dynamic changes in the amplitude of the responses to repeated cAMP injections. The possible role of the retaining current in the origin of the potentiation of cAMP responses was investigated. Potentiation of cAMP responses was preserved after the retaining current was switched off only in cases with no membrane depolarization due to spontaneous leakage of the substance from the microelectrode. It is suggested that potentiation or depression of cell responses to repeated cAMP injections is caused by dynamic changes in the cell cAMP system.

Animals↗
PubMed1983

[Atypical responses to dopamine of Helix pomatia neurons].

Atypical dopamine responses of Helix pomatia neurons accompanied by a fall in passive membrane permeability (an increase of the input resistance) were discovered. The reversal potential of the depolarizing atypical response amounted to -83 +/- 7 mV, and that of the hyperpolarizing response to -15 -20 mV. These values coincided with the reversal potentials for the hyperpolarizing and depolarizing responses to dopamine, that developed as membrane permeability increased. Biphasic dopamine responses are also described, in which the first phase is determined by an increase, while the second one with a decrease of membrane permeability. It is suggested that atypical dopamine responses are associated with specific types of ionic channels and are mediated via specific dopamine receptors.

Animals↗
PubMed1983

[Selective reduction by morphine and enkephalins of depolarization induced by application of dopamine to Helix pomatia neurons].

Morphine, met-enkephalin and leu-enkephalin (1 . 10(-5)M) rapidly, reversibly and in a naloxone-dependent manner depressed the amplitude of dopamine-induced depolarization in neurons of the snail Helix pomatia. Dopamine hyperpolarization and both types of responses to acetylcholine were not altered by morphine and enkephalins. A hypothesis of Zieglgansberger on a blockade of chemically excitable sodium channels by morphine and enkephalins is discussed. It is suggested that opiates block sodium channels when they are applied in high concentration (1 . 10(-4)-1 . 10(-3)M). Lower concentration of morphine and enkephalins (1 . 10(-5)M) modulate the neurotransmitter postsynaptic responses perhaps by means of affecting the cyclic nucleotide system.

Acetylcholine↗
PubMed1982

[Seasonal characteristics of the action of morphine and naloxone on the dopamine response of Helix neurons].

Morphine (1 X 10(-5) M) depresses the dopamine responses of Helix neurons in the summer-autumn period. The depolarizing responses are depressed more powerfully than the hyperpolarizing ones. Naloxone (1 X 10(-5) M) has no effect on the dopamine responses but antagonizes the effect of morphine. In the winter-spring period, the morphine effects are less potent (P less than 0.02), while naloxone depresses the dopamine responses. The results show the plasticity of the opiate-neurotransmitter system and relationship of the latter with the functional status of the body (hibernation, activity).

Animals↗
PubMed1981

[Naloxone-dependent morphine-induced depression of the snail response to serotonin].

Morphine which was added to the extracellular solution in a concentration of 1.10(-5) M, rapidly and reversibly depressed depolarizing (15 cells of 20) and hyperpolarizing (6 cells of 12) serotonin (1.10(-6) M) responses of neurons of the mollusc Helix lucorum. The depressing morphine effect was antagonized by naloxone (1.10(-5) M). The results suggest involvement of an opiate receptor mechanism. Dose-response curves for serotonin before morphine application and in the presence of morphine show a noncompetitive mechanism of morphine-serotonin interaction.

Animals↗
PubMed1981

[Naloxone-dependent morphine reduction of excitatory responses of mollusk neurons to dopamine].

Morphine injection into the perfusate at a concentration of 1 x 10(-5) M rapidly and reversibly inhibits depolarizing rather than hyperpolarizing responses of Helix pomatia neurons induced by dopamine (1 x 10-5). The depressant effect of morphine is completely reversed by naloxon (1 x 10(-5) M). The results suggest the involvement of an opiate receptor mechanism. The dose-response curves for dopamine before morphine application and in its presence indicate a noncompetitive mechanism of interaction between morphine and dopamine.

Animals↗
PubMed1979

[Effect of schizophrenic patients' serum immunoglobulins on nerve cell potentials].

With the aid of the microelectrode method, the influence of different protein fractions isolated from the blood serum of schizophrenic patients and normals on an edible snail was studied. The fractions were isolated by means of ion exchange chromatography and contained immunoglobulins (IgG, IgA, IgM). It was established that the fraction of the blood serum in schizophrenic patients, containing IgM is significantly stronger than the respective fraction in normals, depolarizing and inactivating the neuron membrane. It is suggested that there is an increased content of tropic to the nervous tissue antibodies of this class in the blood serum of schizophrenic patients.

Animals↗
PubMed1978

[Possible role of genetic factors in increasing the serum neurotropic activity of schizophrenic patients].

The authors studied the accumulation of individuals with an increased neurotropic blood serum activity among the relatives of schizophrenic patients. In order to evaluate the degree and character of the genetical determination of the biological indices 2 independent approaches were used: the method of a sequential search of genetical significant threshold values of signs (within the framework of a poligenic Falkoner-Edwards model) and the method of a partition of the total phenotypic variance into main compounds on the basis of intrafamilial correlations. It was demonstrated that the studied signs are characterized by a very high degree of a genetical determination. It is assumed that the small amount of specific loci (major genes) with the effect of intraloci dominance or intraloci epistatic interaction are responsible for the given biological marker.

Genes↗