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Biomedical subjects

V V Raevskiĭ

Publications and source records attributed to V V Raevskiĭ.

At least 19 recordsLinked to original sources
PubMed2002

[Endogenous dopamine modulates cortico-pallidal influence via GABA].

Sprague-Dawley rats were used to study the influence of local application of antagonists of D1 and D2 receptors (SCH 23390 and raclopride, respectively) on neuronal responses in globus pallidus evoked by somatosensory cortex stimulation. SCH 23390 was found to produce a short-latency inhibition in response to cortical stimulation and to block the long-latency inhibition. Raclopride application suppressed the short-latency inhibition and revealed the long-latency inhibition in response to cortical stimulation. It is suggested that the observed phenomena are based on the modulation of GABA releasing in stria-pallidar terminals by endogenous dopamine.

Animals↗
PubMed1982

[Correlations of the geometric and electrophysiologic characteristics of brain stem neurons in the kitten].

Spike activity of the medially and laterally localized units was compared in the pontomedullar reticular nuclei on 1-5 and 15-30 day old kittens. The amplitudes of spikes, spontaneous and evoked patterns of firing in the lateral and medial groups were different. The ratio of cells responding to single and high-frequency stimuli was lower in the lateral units and higher in the medial ones. The medial units had a more significant background firing activation in the interstimulus intervals. It is supposed that the medial cells reflect the properties of densely ramified giant neurons and the lateral--those of the sparsely ramified units. The difference between their electrophysiological properties may be connected with the dendrite geometry, especially with maximal branching foci of dendrites.

Action Potentials↗
PubMed1981

[Role of raphe nuceli in the development of somatosensory cortex neuronal activity in the kitten].

The formation of background and evoked unit activity in the I somatosensory cortical zone was traced in acute experiments on 5 to 20 days old kittens. Stimulation of anterior (median, dorsal) raphe nuclei inhibits the spike activity of cortical units in kittens beginning with the age of 11 to 12 days and modulates evoked responses. This is manifested in the transformation of immature tonic reactions into phasic, which are inherent in a more definitive type of reaction. The role of the serotoninergic mechanisms in the formation of recurrent inhibition in the cortex is discussed, as well as heterochroneous formation of monoaminergic brain systems in the process of postnatal development.

Age Factors↗
PubMed1979

[Electrophysiologic and chemoreceptive characteristics of pontomedullary and thalamic neurons during the process of ontogenetic development].

The background and evoked activity of reticular units in the medulla, pons and ventrobasal complex of the thalamus was studied on cat's fetuses and kittens 54-65 and 1-60 days old, respectively. 63% (pons) and 92% (medulla) of spontaneously active cells were recorded in the fetuses. The highest percentage of evoked responses (60% in the fetuses) was observed upon stimulation of the tongue. Repeated application of stimuli facilitated the firing during the interstimulus intervals, especially during the early developmental stages. Sensitivity to transmitters in the fetuses was maximal to noradrenalin (87%) and glutamate (70%) and minimal to acetylcholine (43%). With development of the animal the number of adrenosensitive units decreased, that of the cholinosensitive increased, and the sensitivity to glutamate remained at the same level. A conclusion is made that the synaptic processes at early developmental stages are mainly of adrenergic and glutamate nature.

Acetylcholine↗
PubMedDate not supplied

[The effect of forelimb deafferentation in early postnatal ontogeny on the development of synaptic transmission in the hippocampus].

Hippocampal slices from 15-20-day-old Wistar rats were used to study the development of some features of synaptic transmission in hippocampus and the influence of partial limitation of the sensory inflow in the early ontogeny of this transmission. The dynamics of population spike changes was observed in the CA1 hippocampal field in response to stimulation of Schaffer collaterals. The early ontogenetic limitation of the sensory inflow was accomplished by cutting n. medianus on the 13th day. Between the 15th and 20th days, the dynamics of the population spike amplitude increase in the control and experimental animals was similar, however, the response amplitude of the control rats remained higher than in the experimental animals throughout the whole period of observation. It is suggested that the partial limitation of sensory inflow from a forelimb at the early stages of the ontogeny alters the formation of synaptic transmission in hippocampus.

Afferent Pathways↗
PubMedDate not supplied

[Does the destruction of the catecholaminergic neurons in newborn rat pups influence the modulatory function of the cholinergic system?].

On outbred ratlings aged 21-31 days the influence was studied of the destruction of catecholaminergic (CA) system on the reactions of the neurones of the cortical somatosensory zone, elicited by the stimulation of the ischiatic nerve and modulation of these reactions after stimulation of the basal nuclei area (the source of the neocortex cholinergic innervation) and acetylcholine (ACh) microiontophoretic application. It is shown that destruction of CA system in newborn ratlings increases the reactivity of the somatosensory cortical neurones in 21-31 days old animals to sensory stimulation; it does not influence the efficiency of modulating action of the cholinergic system of the forebrain and leads to the increase of modulating influence of the applicated ACh. It is postulated that as the result of perinatal destruction of CA brain system, in the neocortex a specific morpho-functional organization is formed of structures and processes at which the modulating function of the forebrain cholinergic system turns out, by quantitative criterion, at least, to be compensated.

Acetylcholine↗
PubMedDate not supplied

[The role of visual afferentation in the development of early defense behavior of pied flycatcher nestlings].

The development of defense behavior in normal and visually deprived pied flycatcher nestlings was studied in the wild. It was demonstrated that the young deprived of the visual afferentation did not develop the freezing posture. In the majority of cases, specific alarm call suppressed begging in visually deprived nestlings less effectively than in the control ones. Visually deprived nestlings could not discriminate between the alarm call and other rhythmically organized acoustic signals even though the latter effectively suppressed begging.

Acoustic Stimulation↗
PubMedDate not supplied

[Formation of serotonin- and GABA-ergic mechanisms of synaptic transmission in the cat neocortex during early ontogenesis].

In acute experiment on 5-20 days kittens, the reactions were studied of neurones in the cortical somatosensory zone to stimulation of the dorsal raphe nucleus (DRN) and application of serotonin, ethanolamine-O-sulphate and bicucullin. The identity is established of the effect of DRN stimulation and serotonin application eliciting inhibition of the background activity and appearance of inhibitory phases in response to sensory stimulation, beginning from the 10-12th day after birth. A suggestion is made about serotoninergic regulation of GABA-ergic interneurones' in young animals. The dynamics of GABA-ergic brain system formation has been studied. Specific sensitivity of neocortical neurones to GABA increased to the end of the second week of life--the period when modulating serotoninergic influences appear.

Aging↗
PubMedDate not supplied

[The cholinergic system of the forebrain modulates the activity of the GABA-ergic interneurons which realize presynaptic regulation in the neocortex of kittens].

It has been found that at the end of the second week of postnatal life, stimulation of cholinergic ascending paths causes a selective inhibition of cortical neurones reaction to sensory stimulation, without influencing the background activity. The observed inhibition is blocked both by atropine and picrotoxin, but not by bicuculline. It is suggested that the observed phenomenon characterizes, presynaptic control of cortical neurones activity in the early ontogenesis. This inhibition is formed on the basis of cooperative choline- and GABA-ergic brain systems participation and is performed not through GABA-receptors.

Animals↗