Biomedical subjects
Publications and source records attributed to G G Khludova.
Dependence of changes in the postsynaptic density, active zone and synaptic cleft on time relations between the administered associated stimuli was established. Locally applied glutamate and acetylcholine were used as the stimuli.
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.
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.
An ultrastructure comparison of presynaptic and postsynaptic components of axodendritic synapses of the fifth layer of rats neocortex sensomotor region after microionophoresis of acetylcholine and physiological solution has been carried out. The absence of true differences is considered as an adequacy indicator of application mediator regime.
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The connection of the dimple zone of the somatic sensory cortex with a lateral area of gyrus cruciatus in the motor cortex was investigated by means of the Nauta-Gygax, Fink-Heimer techniques and retrograde axonal transport of horseradish peroxidase. A height degree of differentiation is detected in organization of transcortical sensomotor projections. The pyramidal, stellate and inverted pyramidal cells of the third layer of he cortex participate in formation of these ways. Th data obtained by the experimental degeneration method and electron microscopic technique show that hte afferentation from the first somatic sensory area terminates mainly on dendritic spines in layers III and V and partly on elements in layer I in the motor cortex. It is suggested that the associative fibres exert their action on the projectional neurons of the motor area directly or through inter-neurons.
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A morphometric investigation of various components of the synapses of neurons of the sensorimotor region of the cerebral cortex of rats with different variants of combined and uncombined repeated microiontophoretic application of glutamate and acetylcholine has been carried out. A substantial dependence of the character and expressivity of the reorganizations of the thickness of the postsynaptic density (PSD), of the width of the synaptic cleft, and the length of the active zone of the synapses, on the temporal relationships in the action of mediators has been identified: significant changes in the thickness of the PSD appeared only with the combined applications of the stimuli (neuromediators); the maximum thickening of the PSD was induced by the combined action of glutamate and acetylcholine with a 3-second delay in the latter. A hypothesis is presented according to which the temporal specificity in the integration of associable signals arriving at neurons is determined by the kinetics of the various interacting biochemical regulator mechanisms.
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The relationship between structural changes in postsynaptic densities of axodendritic synapses and the sizes of postsynaptic ribosomal aggregations were studied. A positive correlation was found between the thickness of the postsynaptic density and the number of ribosomes. The role of dendritic mRNA and the possible mechanisms supporting rapid local protein synthesis during the modification of postsynaptic components is seen on combined administration of two neuromediators into the rat neocortex.
Electrical stimulation (50-100 pulses, 100-500 Hz) of the ventral tegmental area (VTA) in the vicinity of the n. interpeduncularis in the frontal plane AP2-AP4, L1-L2 caused a cat to grab food placed near its mouth. The conditioned forepaw placing reaction was elaborated using food reinforcement and VTA stimulation as a conditioned stimulus. The conditioned reflex, being once established, was repeatedly performed without extinction in the course of up to 250 trials without food reinforcement. Short (5-10 pulses) conditioned VTA stimulation evoked a prolonged (up to 1000 ms or longer) activation of neurons of the motor cortex and caused a substitution of the inhibitory phase of response to stimulation of the parietal cortex in poststimulus interval in 50-200 ms for the late secondary excitatory response.