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V V Senatorov

Publications and source records attributed to V V Senatorov.

At least 37 records · Page 2Linked to original sources
PubMed1993

Depolarizing action of secretory granule protein 7B2 on rat supraoptic neurosecretory neurons.

A novel precursor neuropeptide termed 7B2 is present within specific brain areas, including the hypothalamic magnocellular neurosecretory neurons, and appears to be processed to smaller fragments. In order to determine whether specific C-terminal fragments of 7B2 might exert local effects on neurosecretory cells, we used intracellular current-clamp recordings in supraoptic neurons maintained in superfused hypothalamic explants to evaluate membrane potential and resistance changes in 25 supraoptic nucleus neurons during bolus applications of 7B2 174-186 and two other C-terminal peptide fragments 7B2 156-173 and 7B2 141-150. In 15 supraoptic neurons, only the 7B2 174-186 fragment induced a gradual 2-8 mV membrane depolarization that lasted for 4 to 30 min and was accompanied by 15+/-8% reduction in input resistance. Immunocytochemical identification of the recorded cells revealed that both vasopressin (VP)- and oxytocin (OT)-containing neurons were depolarized by 7B2 174-186. These data suggest that 7B2 174-186 is a biologically active fragment of 7B2 and may regulate the excitability of magnocellular supraoptic nucleus neurons.

Animals↗
PubMed1991

Electrophysiological and morphological properties of embryonic neocortical grafts developing in different regions of the host rat brain.

Parallel morphological and electrophysiological studies of embryonic neocortical tissue (primordia of anterior parietal--presumptive sensorimotor--cortex) grafted into different regions of the host adult brain (sensori-motor cortex, caudate-putamen, septum or thalamus) were carried out to investigate to what extent the properties of transplanted embryonic neocortex--an advanced organizational form of neuronal tissue--are affected by homotopic or heterotopic surroundings. The results point to the importance of the host tissue environment as it influences both the size, the morphological and functional properties of the implanted embryonic cortical plate tissue. The cortical grafts were smaller in size when developed homo-topically in sensorimotor cortex and grew larger in heterotopic environment (caudate-putamen, septum, thalamus). The orientation of neuronal dendrites in the grafts tends to follow that seen in the surroundings. The homotopic grafts showed a better structural integration into the host brain. Differences were seen between intracortical and subcortical transplants in the spontaneous firing rate of neurons and in the ratio of units with various types of spontaneous discharge.

Animals↗
PubMed1990

[Afferent and efferent connections of cortical transplants implanted into the damaged sensorimotor area of the cerebral cortex of mature rats].

Afferent and efferent connections of the transplant, implanted in the previously damaged sensorimotor area of the mature rat cerebral cortex have been studied by means of axonal transport of horseradish peroxidase. For 5 months after transplantation neural axons of the transplant are capable to reach the caudo-putamen and thalamic structures, while connections with the spinal cord are absent. The afferent connections of the transplant are minimal and belong only to the neighbouring areas of the cortex and the caudo-putamen of the recipient brain. Presence of efferent projections to the striate and thalamic structures demonstrates specificity of the projections formed; this can be a morphological base for restoration of the functions lost after the damage of the sensorimotor area of the cortex in mature animals.

Animals↗
PubMed1987

[Homotopic transplantation of embryonic neocortical tissue into the brain of adult rats after its damage].

Structural characteristics (survival, growth, connections) have been studied in the transplant of the cerebral cortex tissue in Wistar rat embryos (18-day-old), implanted into the brain of mature rats of the same line at various time after a partial lesion of the sensomotor cortex. In 3-5 months after transplantation the light microscopy methods demonstrate that spatial interconnections of the transplant and the injured brain of the recipient depend on time interval between the cerebral lesion and transplantation of the embryonal nervous tissue. Horseradish peroxidase (HP) is ionophoretically injected into the recipient's cerebral tissue away from the place of transplantation. In the transplant retrogradely labelled HP neurons are revealed. This demonstrates efferent connections of the implanted tissue with the host's brain. Presence of the anterogradely labelled nervous terminals in the transplant tissue demonstrates existence of afferent connections of the transplant with the recipient's tissue. Possible mechanisms of survival, growth and formation of connections of the transplant in the injured brain of the mature animal are discussed.

Animals↗
PubMed1986

[Changes in the functional characteristics of cells of the Clare-Bishop zone after unilateral partial isolation of the cat neocortex].

Evoked single cell activity in the Clare-Bishop area of the cat neocortex was recorded after partial transection of subcortico-cortical connections. Both functional properties of visual, auditory and somatosensory responsive cells and their responses to electrical stimulation of the primary projection area were studied. A week after transection some neurons in the Clare-Bishop area on the operated site recovered their reactions to applied stimuli. Within the first week the sensitivity of the neurons in the intact hemisphere changed; all the recorded cells reacted to light; 80% of the cells had receptive fields that were situated in the contralateral part of the visual area; 62% of the cells reacted to somatosensory stimuli. A week after the operation the number of responsive cells decreased. The peculiar features of the neuronal compensatory reorganization in the Clare-Bishop area and its role in the recovery of visual function is discussed.

Animals↗
PubMed1986

[Features of the morphofunctional organization of the embryonal nerve tissue of a transplant into the brain of the adult rat].

Foetal CNS tissue was implanted into different sites of mature rat brain. Analysis of morpho--functional organization and unit activity of the grafts was made 2-5 months after the implantation. Correlations among morphological and functional characteristics of the grafts and sites of the implantation are discussed. Morphofunctional peculiarities of the grafts seem to be due to heterogeneous influences of the host brain.

Action Potentials↗
PubMed1985

[Long-term reorganization of the neuronal activity in field 7 of the neocortex in the cat after unilateral section of the visual radiation].

Changes in functional characteristics of area 7 cells were studied in cats under semichronic experimental conditions. The experiments were done in various periods of time after unilateral dissection of visual subcortic-cortical fibres. Neuronal responses to visual, auditory, somatic stimuli and electrical stimulation of primary cortical areas were studied in intact and impaired hemispheres. Reappearing of neuronal sensitivity to stimuli of various sensory modalities was found in the partially isolated neocortex. Both the number of cells with local visual receptive fields and averaged receptive field size of the cells increased slowly after the operation. Some suggestions about the nature of plastic changes developing in neuronal nets of the parietal cortex after impairment of subcortico-cortical connections are made.

Animals↗
PubMed1981

[Organization of afferent inputs of the parietal association area (field 7) and the Clare-Bishop zone of the neocortex in the cat].

The neuronal response of two parietal fields to the adequate stimuli of different modalities and direct electrical stimulation of various cerebral cortex fields were studied in semichronic experiments on cats. About 40% of the neurons in the Clare-Bishop area responded to the visual stimuli. Cells responding to the stimuli of different modalities were found in the Clare-Bishop area. Considerable percentage of cells in this area reacted to the direct electrical stimulation of area 17. 27% of the studied neurons in area 7 responded to the visual stimuli. As compared with the Clare-Bishop area only a small percentage of cells in area 7 reacted to the stimulation of the primary sensory fields. Electrical stimulation of area 7 was found to inhibit evoked and background activity of neurons in the Clare-Bishop area. A hypothesis is discussed that the areas in question are associative representation of two different sections of the visual system: retino-geniculo-cortical and retino-tecto-thalamo-cortical.

Afferent Pathways↗
PubMedDate not supplied

Influence of nembutal on the impulse activity of cells of embryonal nervous tissue transplanted into the rat brain.

The average frequency of the impulse activity of neurons of an allograft of embryonal cortex, in the brain of adult Wistar rats, under nembutal anesthesia was four times lower than in nonanesthetized animals; at the same time the variability of the activity of the cells of the graft, with respect to the frequency and pattern of impulse activity, decreased. As compared with the unanesthetized animals, half as many cells of the graft reacted to tactile stimulation of the contralateral hind extremity; the neuronal reactions to the stimulation of somatic receptors of the ipsilateral side of the body completely disappeared.

Anesthesia↗
PubMedDate not supplied

[The effect of nembutal on the cellular pulse trains of embryonic nerve tissue transplanted into the brain of the rat].

Under nembutal anaesthesia the mean frequency of single unit discharges recorded from allografts of the rat brain was four times lower than the one measured in unanaesthetized animals. A diminished variability was revealed of firing rates and discharge patterns of the cells within grafts in anaesthetized rat brain. In comparison to unanaesthetized animals the number of graft units reacting to a tactile stimulation of contralateral hindlimb of the operated animals was twice lower. Nembutal anaesthesia provoked a full blockade of reactions to the tactile stimuli applied to the ipsilateral side of the animal body.

Animals↗