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T A Safonova

Publications and source records attributed to T A Safonova.

At least 19 recordsLinked to original sources
PubMed1997

[An improvement on the adhesive electrode recording device].

An improved device of the adhesive electrode for recording the bioelectrical potential of animal's syncytial tissue is described in this paper. The main feature of the new device is to place a small chamber between the syringe for building negative pressue and the adhesive electrode. This chamber can keep the electric connection between amplifier and the tissue being recorded, and be placed near the tissue. The negative pressure can be conducted from the syringe by a plastic tube, so the syringe can be placed in any place where it doesn't affect the experiment. By using this new device, good results can be achieved when bioelectrical potential of hearts or gastric muscle of molluscan snails or frogs etc. is recorded. This simple and easy-operating device is practically valuable on studies of the normal functions and pharmacological effects in small animal's syncytial tissues such as heart, and gastric muscle.

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PubMed1994

[Heart-stimulating neurons in the subesophageal ganglia of the African snail Achatina fulica Férussac].

5 cardiostimulating neurons belonging to 3 different functional groups were studied in visceral and right parietal ganglia of the African snail. The cell VG-1 formerly believed to be an interneuron, was shown to be a motoneuron of the heart producing the EPSPs in the myocardium. The data obtained show a considerable similarity in organization of the cardioregulating neurons system in different species of the gastropods.

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PubMed1990

[The central neurons that inhibit the work of the heart in the edible snail].

The neurones causing the inhibitory postsynaptic potentials (IPSP) with duration 150-200 ms in the myocardium have been identified in the visceral ganglion of Helix pomatia. The neurones are characterized by the high frequency of discharges (2-3 c/s) which changes modulate the heart frequency. IPSP is blocked by d-tubocurarine in the concentration 5.10(-5)-1.10(-4) M.

Animals↗
PubMed1984

[Regulation of snail heart contractions by neurons of the visceral ganglion].

The system of neurons regulating the frequency and strength of heart beats was studied in the snail subesophageal ganglia. Three out of four neurons exerted a short-term phasic effect on the heart. Stimulation of the V6 neuron led to a prolonged increase in the frequency and strength of the heart beats. Activity of two inhibitory cells (about 1-3/sec) was observed whereas excitatory neurons were silent. All the efferent neurons were involved in parallel and did not affect each other.

Animals↗
PubMed1979

Microelectrode investigations of learning phenomena in snail (Helix pomatia) neurones.

We have examined changes of postsynaptic potentials and of pattern activity of the identified silent and oscillatory snail neurones in Helix pomatia during conditioning. Local changes of EPSP or IPSP have been recorded during association following the first stimulus in the silent cells, whereas spike discharges could be observed in response to the 2nd stimulus. In the oscillatory neurones changes of pattern activity have been recorded following the 2nd stimulus, while the first stimulus proved to be ineffective. The formation of temporary connections of snail neurones seemed to be a specific phenomenon, because it was necessary to pair stimuli of different inputs for the development of these modifications. These plastic changes seemed to depend on the interstimulus as well as on the intertrial intervals. Our experimental data underline the probable role of the stimulus parameters and of the electrical properties of neurones during the formation of learned neuronal responses.

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PubMed1979

The passive electrical characteristics of giant neurones identified in the central nervous system of Lymnaea stagnalis.

The passive electrical characteristics of four giant neurones in the CNS of Lymnaea stagnalis were studied. The parameters were calculated on the basis of potential transients evoked by hyperpolarizing square impulses. The examined neurones can be classified in two groups, which show significant differences considering the time constant and membrane resistance. This classification is in correlation with the functional properties of the cells. The differences in the passive electrical characteristics of the giant neurones were compared to some data obtained by using voltage clamp method. The role of these parameters in the generation of the single spike and the rhythmic discharge is discussed.

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PubMed1975

[Electrical characteristics of the sensory neurons of the medical leech].

The electrical characteristics of three types of sensory neurons (N, T and P) were determined in the leech Hirudo medicinalis. Statistically significant differences were found between the values of tau, Cs and Rs in the neurons of N- and T-types. The same parameters show the least variation coefficients. The value of time constant (tau) is 17.000-46 ms, the resistivity of the soma membrane TRs) is 19.50 kphi-cm2 in T-neurons and 35 kphi-cm2 in N-neurons. The surface of the neurons estimated by their capacitance (Cs) can be 4-10 times larger than the surface of a sphere of the same size. The possible influence of electrical characteristics of the neurons on the peculiarities of their electrical reactions is discussed.

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