Biomedical subjects

I E Mikhal'tsev

Publications and source records attributed to I E Mikhal'tsev.

4 recordsLinked to original sources

PubMed1983

[Specificity of the selective sensitivity of electrosensitive neuron membranes to low-frequency sinusoidal stimulation].

A difference in sensitivity of mollusk's neuron to intracellular injection of sinusoidal current (1-10 Hz; 5.10(-10)--5.10(-9) A) was found as well as the complete cessation of activity at certain frequency--amplitude characteristics of the current ("windows" of blocked activity) and an increasing activity at other frequency--amplitude parameters of the current ("windows" of growing activity). This may be due to some properties of the neuron's electrosensitive membrane: the specifics of the voltage--current characteristics, membrane capacity as well as the property known as "force--duration" relationship. The key importance lies in the dependence of the hyperpolarization of the neuron upon the amplitude and the frequency of the sinusoidal irritant.

Action Potentials↗

PubMed1983

[Changes in the input resistance and membrane potential of a neuron developing a trace effect].

Trace effects in the change of spike activity, input resistance (Rinp) and membrane potential of neurons of the mollusk brain were studied in 36 "silent" brain neurons of Limnaea stagnalis in conditions of 20-min intracellular application of sinusoidal current with the threshold frequency 0.1 Hz. Some neurons revealed the effect of facilitation: the rise of activity with membrane depolarization and an increase of Rinp. Other neurons revealed the fall of activity accompanied by hyperpolarization and a decrease of Rinp. The change of Rinp as a trace effect is at its maximum at the frequency of the current used in the intracellular application. This suggests that the neuronal plasticity in "learning" is just based on the Rinp trace effects. Some of the neurons revealed no change in Rinp, membrane polarization or electrical response to applied stimulation. Possible origin of the above effects is discussed.

Animals↗

PubMedDate not supplied

Variation of the input resistance and membrane potential of a neuron in trace formation.

Trace changes in electrical activity, input resistance (Rinp), and membrane potential (MP) of brain neurons are studied in the mollusk Limnaea stagnalis for intracellular stimulation with a sinusoidal threshold current with a frequency of 0.1 Hz during 20 min. Some neurons are shown to exhibit an effect of facilitation, a rise in the level of activity being attending by an increase in Rinp and depolarization. Other neurons displayed lowered activity with a decrease of Rinp and hyperpolarization. The selectivity of the Rinp variations relative to the parameters of the stimuli (maximum changes at the frequency of the current used) suggests that it is precisely trace changes of Rinp which lie at the basis of the neuronal plasticity in "learning." Some neurons in this series of experiments did not alter their electrical response, Rinp, or MP for stimulation. The possible reason for the non-uniform reaction of different neurons to identical stimulation is discussed.

Animals↗

PubMedDate not supplied

[Quasielectrostatic manipulation of a single neuron: trace phenomena and comparison with intracellular excitation].

The investigation of quasielectrostatic impact (QESI) on the electrical activity of an isolated neuron of the mollusc brain was continued under conditions of continuous (20 min to 2 hours) and repeated applications. It was shown that the repeated application of QESI changes the level of electrical activity of the neurons. For different cells the repeated application of QESI produces an increase as well as a decrease of the neurons activity, while the thresholds of the frequency modulation of the spontaneously active and the excitation of the "silent" cells become lower. These changes remain valid after QESI is stopped. The trace events shown on the level of an isolated neuron prove the importance of the properties of a single cell, rather than the intercellular interactions. The transmembrane current thresholds for FM of activity of the cells produced by QESI was compared with the currents for intracellular stimulation. It was shown that the QESI thresholds are lower being different cells (2 divided by 12) times less. The specificity of QESI important for explanation of ephatic connection mechanism is discussed.

Animals↗