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Biomedical subjects

B I Kotliar

Publications and source records attributed to B I Kotliar.

At least 19 recordsLinked to original sources
PubMed1990

[The negative shift in the reversal potential of the acetylcholine-induced incoming current in the RPa3 and LPa3 neurons of the edible snail during its extinction].

A negative shift of reversal potential at its extinction has been found with the current-voltage relation of acetylcholine-induced inward current in Helix lucorum's RPa3 and LPa3 neurons. An assumption has been made on a nonuniform extinction of acetylcholine-induced currents which is due to the motion of different ions. Ion flow with a more positive equilibrium potential decreases to a greater degree than reversal potential. It can be a current of Ca2+ and/or Na+ ions.

Acetylcholine↗
PubMed1989

[An experimental approach to research on the integrative properties of a single brain neuron].

The difficulties in investigation of the single neuron integrative properties in mammalian brain are connected with the absence of a mean of determination of neuronal set contribution in their activity. In given paper an experimental approach to the decision of this task is proposed. It consists in neuron activity investigation in the model learning training situation under condition of partial functional isolation from nervous cells by means of decrease in extracellular calcium concentration level using ethylene glycol tetraacetate. As indicator of such isolation was a partial or total reduction of responses in investigated neurons to electric microstimulation of neighbouring (200-240 mkm) parts of neocortex. The results of analysis of neuron responses in sensomotor cortex in the rat's brain in the process of acetylcholine repetitive local application give possibility to propose that some neurons don't exhibit plasticity according to the indicator in the dynamics of impulse discharge rate in responses to transmitter.

Acetylcholine↗
PubMed1989

[Second messengers in the regulation of nerve cell plasticity during learning].

A review of 1972 to 1988 publications is presented, as well the data obtained by the authors on the influence of second messengers and their intracellular receptors on neuron plasticity in the learning experimental models. The emphasis is laid on cyclic 3',5'-adenosine monophosphate; cyclic 3',5'-guanosine monophosphate, calcium ions and their intracellular receptor calmodulin, as well as on the metabolites of phosphoinositide exchange: inositol-1, 4, 5-trisphosphate, 1,2-diacylglycerol and protein kinase C activated by the latter and arachidonic acid.

Animals↗
PubMed1989

[Protein kinase C is not involved in regulating the short-term cholinoreceptor plasticity of the PPa3 and LPa3 neurons of the edible snail].

A voltage clamp technique on identified Helix lucorum's RPa3 and LPa3 neurons has been used to negate the effect of protein kinase C on extinction of response to repeated iontophoretic applications of acetylcholine to soma. Extracellular influence of phorbol ether, protein kinase C activator (12-O-tetradecanoylphorbol-13-acetate, 0.1-10 mumol/l), or polymyxin B, its blocker (100-500 mumol/l), do not affect the extinction of acetylcholine-induced neuronal response. The data show that protein kinase C is not involved into molecular mechanisms responsible for the regulation of short-term plasticity of RPa3 and LPa3 neuronal cholinoreceptors in Helix lucorum.

Acetylcholine↗
PubMed1988

[The role of cyclic 3',5'-adenosine monophosphate in the extinction of the reaction of identified neurons in the edible snail to acetylcholine].

The recording of transmembrane currents and intracellular potentials has been used to show on Helix lucorum identified neurons RPa4, RPa3 and LPa3, that pharmacologic effects on adenylate cyclase system do not influence the extinction of neuronal response to repeated local iontophoretic applications of acetylcholine to the soma. Neither cAMP-raising adenylate cyclase activator forskolin (2-6 x 10(-5) mol/l), nor cAMP-lowering phosphodiesterase activator imidazole (5 x 10(-3) mol/l) alter the dynamics of extinction of response to acetylcholine. A conclusion has been made that shortterm plasticity of cholinoreceptors in the investigated neurons is independent of intracellular cAMP level.

Acetylcholine↗
PubMed1988

[Plasticity and its physiological markers in the microsystem of cortical neurons during repeated local stimulation].

Separate neuronal microsystems in the sensomotor cerebral cortex are able to exhibit the functional plasticity under conditions of repeated action of acetylcholine applied microiontophoretically. The characteristic properties of dynamics in activity of single cortex neurones are determined mainly by the initial reactivity to transmitter and by the state of nervous cells of the surrounding microsystem. The composition and succession of response components as well the duration of excitatory stage of reaction to acetylcholine serve as physiological markers of plastic properties of neurones in cortical microsystem.

Acetylcholine↗
PubMed1988

[Integrative properties of the microsystem of cortical neurons during repeated local stimulation].

Small groups of neighbouring neurons in neocortex are able to form separate microsystem in model situation of habituation during the local repetitive action of acetylcholine. This new functional unit exhibits a number of main properties which are characteristic of systemic processes of habituation. Only some of the properties don't reproduce in microsystem of cortical neurons. There is no effect of full extinction of responses and no direct relationship between the decrease of speed quantity of responses and stimulus action frequency. The data obtained are considered as significant argument for identification of special intermediate level of integrative processes--microsystem level.

Acetylcholine↗
PubMed1988

[Learning and memory: neurophysiological mechanisms].

The analytical review of study of neurophysiological basis in different kinds of learning and memory in animal and human is given. The main attention is paid to the consideration of systemic and neuronal levels of habituation and conditioned reflexes. A conception on the brain functional state as the main mechanisms of learning and distributed multicomponent engram corresponding to the integrative process peculiarities is developed.

Animals↗
PubMed1987

[Reactions of neurons in the sensory-motor cortex on different amounts of administered acetylcholine].

As a result of acetylcholine iontophoresis with different currents 3-fold increase of transmitter compared with the threshold one for reaction has been shown not to result in change of a type of reaction pattern more than in 80.3% of neurones. Such increase of action force is quite enough for the significant lengthening of the reaction excitatory components in the most of investigated neurones. After the following repeated application of smaller quantity of transmitter the number of neurones with growth of frequency of excited impulsive activity recovers as well as the level of firing frequency decrease in the course of repetitive administration of transmitter. The effect of large doses of transmitter results in aftereffect expressed by increasing probability of excitatory component reduction during the repetitive applications of acetylcholine.

Acetylcholine↗
PubMed1986

[Nature of the activity of cerebral cortical neurons in the case of their partial reversible functional isolation using EGTA iontophoresis].

The EGTA iontophoresis influence on activity of 63 neurons of the rat's sensomotor cortex has been investigated. Neurons with high and low sensitivity to calcium ions decreasing level in extracellular medium have been found. A possibility of partial reversible functional isolation of neuron from neuronal net by blocking the transmitter release by EGTA has been shown.

Animals↗
PubMed1986

[Detection of the activation of the motor cortex of the cat during movement of an extremity using thermomapping of the brain].

In chronic experiments on cats the distribution of temperature on the dorsal surface of the cerebral cortex and its dynamics were studied through unopened skull by the thermovision and digital image processing technique. During the reflex movement of the forelimb and after it focal biphasic thermoreactions in the motor cortex which lasted for up to 30 s and sign-opposite thermoreactions in symmetrical points of both hemispheres were revealed.

Animals↗
PubMed1986

[Reactivity of the cholinoceptive cortical neurons to the repeated action of acetylcholine].

Three groups of sensorimotor cortical cholinoceptive neurons have been established in albino rats according to the dynamics of reactivity to repeated action of acetylcholine. There are neurons with decreased, increased or unchanged response to transmitter microintophoretic application. Dependence of the dynamics of background and evoked activity on the duration of excitatory reaction component induced by transmitter has been discovered. It was concluded that the duration of the given component is a significant and informative functional parameter of cortical neurons.

Acetylcholine↗
PubMed1985

[Changes in the ultrastructure of synapses of neurons of the cerebral cortex of the rat in response to isolated and combined microapplications of mediators].

Presynaptic and postsynaptic ultrastructure components in the axo-dendritic synapses of layer V of the rat sensomotor cortex were compared after isolated and combined microionophoretical applications of 1-glutamate and noradrenaline. An increase in the width of the postsynaptic density was established in case of combined glutamate and noradrenaline applications. Both isolated and combined transmitter applications decreased the quantity of synaptic vesicles in the terminals. The data are considered as evidence of modulatory action of noradrenaline on other neurotransmitter systems.

Animals↗