Search PubMed⌕ Search

Biomedical subjects

F N Makarov

Publications and source records attributed to F N Makarov.

At least 19 recordsLinked to original sources
PubMed2000

[A morphological analysis of the cluster organization of the cortico-cortical neurons in area 17 of the cat visual cortex].

Spatial organisation and quantitative features of cortico-cortical neurons in area 17 that project to area 21a of cat visual cortex were investigated. We used the HRP technique and two-dimensional reconstruction from serial sections of brain. Pattern of distribution of labelled cells in some regions of areas 17 and 18, on the lateral and medial surface of the brain were analysed. The data about cluster organisation of cortico-cortical neurones, localisation, layer distribution and density of neurons were obtained.

Animals↗
PubMed2000

[The spatial distribution of the horizontal connections in area 18 of the cat cerebral cortex].

Spatial distribution of horizontal inner links in field 18 of cat cerebral cortex was studied after microiontophoretic administration of HRP into a certain cortical column. HRP labelled cell location and their distribution in plane of cortex surface and sagittal and frontal planes were detected. Ellipsoid shape and rostrocaudal direction of the area of labelled cells was demonstrated irrelevant to the column localization in field 18 (stereotaxic coordinates of the columns studied are from P4 to A14). Thus, topography of the field 18 inner links was coordinated with its macrotopography, detect established electrophysiologically.

Animals↗
PubMed2000

[The role of the prefrontal and parietal cortex in learning and memory in monkeys].

Removal of the 7th field of parietal cortex and sulcus principalis of prefrontal cortex did not affect learning processes for images with such properties as spatial frequency, orientation, geometrical form, but worsen learning characteristics in visual differentiation of spatial information making the learning processes unstable, longer and below the 85% level. Removal of sulcus principalis also affects learning of differentiation among various colour stimuli. The short-term memory in these monkeys are also much worse than in intact animals. A scheme of learning involving interacting sensory and cognitive processes controlled by motivation system, is proposed.

Animals↗
PubMed1999

Changes in afferent impulse activity of small intestine mesenteric nerves in response to antigen challenge.

Sprague-Dawley rats (weight 130-150 g) were sensitized by an intraperitoneal injection of 1 mg chicken egg albumin with 0.25 ml Freund's adjuvant to stimulate immunoglobulin E antibody production. Leukocyte migration inhibitory factor was used as an indicator of animal sensitization. In acute electrophysiological experiments on sensitized animals, an intra-arterial or intraluminal chicken egg albumin (100 microg) challenge evoked a 10% enhancement of the activity of mesenteric nerves of the small intestine, regardless of the injection site chosen. Afferent nerve activity in control animals was not changed during the chicken egg albumin challenge. Morphometry at the light microscope level showed activation of mast cell degranulation after the antigen challenge to presensitized rats. Intraluminal injections of a stimulator of mast cell degranulation, compound 48/80 (20-30 mg), were found to increase afferent discharges in intact rats. An antagonist of H1 histamine receptors, clemastine, reduced the effect of compound 48/80. The results obtained provide direct evidence for the stimulation of sensory nerve endings by mast cell mediators released during mast cell degranulation.

Afferent Pathways↗
PubMed1999

[Structure of the interrelations between retinal neuroglia and ganglion cells].

Organization of glial environment of bodies and axons of cat retinal ganglion cells (GC) was analysed electron microscopically. Similarities and differences in types of contacts between macroglial cells and GC plasmalemma throughout its length were demonstrated. Regularities of changes of types of glia surrounding different types of GC were established. GC body was surrounded by the processes of Muller gliocytes, while a special glial crown appearing as multiple radial finger-shaped astrocyte processes covers GC initial segment. Possible functional aspects of structural organization of interrelations of GC body and axons with gliocytes are discussed.

Animals↗
PubMed1998

[Varying intensity and staining of neurons in the cat visual cortex during histochemical detection of horseradish peroxidase].

We have investigated the staining of different types of neurons after horseradish peroxidase injection in the cat striate cortex. The intensity of staining was classified as dark, intermediate, or light. Cells with different staining intensities were found in all cortical layers and at different distances from the injection site. According to the shape of their somata and the organisation of their dendritic trees, the labelled cells were identified as pyramidal, small pyramidal, non pyramidal and modified pyramidal (inverted and fusiform). The ratio of dark:light:intermediate cells within all identified morphological types was 2:1:1, except for the modified pyramidal neurons (1:1:1). Revealed peculiarity of modified pyramidal cells may serve as additional characteristic of this morphological type cells. Thus the intensity of staining depends not only on the physical uptake and transportation of enzyme but also on the organisation of axonal terminals and neuron location in the functional structure of the cortex.

Animals↗
PubMed1998

[Dependence of learning characteristics on visual object properties in Rhesus macaca by bilateral removal of the 7th field of the parietal cortex].

Removal of the rhesus monkey parietal cortex 7th field exerted no effect on learning processes involving visual discrimination of images united in their colour and geometrical form, but the learning of differentiating the spatial information did suffer. The data obtained suggests that, in the process of learning visual differentiation, spatial differentiating signs are formed, the process involving neuronal structures of the 7th field of the inferior cortex. Removal of the 7th field disrupts mechanisms of the body scheme assession and egocentric orientation resulting from visual-vestibular interrelationships.

Animals↗
PubMed1997

[The dorsal motor nucleus of the vagus nerve and its role in innervating the digestive tract].

Findings on topography of dorsal motor vagal nucleus neurons from which axons towards functionally different regions of digestive tract extend were analysed. Based on that and on the data available in literature main peculiarities of these cells topical organization were formulated. It is noted that "gastrointestinal" neurons are localised in dorsal motor nucleus as narrow stripes oriented caudo-rostrad. Stripes (or columns) of neurons from axons towards the digestive trace different parts arise do not cross. Digestive tract oral parts receive parasympathetic efferent inputs from neurons of medial and dorsomedial parts of the nucleus and caudal--from ventromedial cells of dorsal motor nucleus. Sites of maximal accumulation of initial "gastrointestinal" neurons that occupy an area within +0.5-(+)2.0 mm of functionally different regions of stomach and gut were demonstrated in cat and rat.

Animals↗
PubMed1997

[Cytochrome oxidase distribution in the normal cat midbrain and after unilateral enucleation (a histochemical study)].

Histochemical method of cytochrome oxidase demonstration was used to study its distribution in frontal sections of tectum of the midbrain in cat in normal conditions and after unilateral enucleation. Basic layers of this formation were demonstrated in normal conditions similar to those revealed using classical histological methods. After unilateral enucleation rostral, middle and caudal parts of superior colliculus were stained differently. Contra- and ipsilateral surface layers in rostral and caudal parts were stained also with different intensity. Alteration of lightly and intensely stained patches appeared in middle part. Peculiarities of staining in cytochemical cytochrome oxidase demonstration in superior colliculus of tectum of the midbrain in enucleated animals are likely to reflect peculiarities of this structure afferentially by retinotectal, geniculotectal and geniculocortical fibres.

Animals↗
PubMed1997

[The laminar organization of the afferent connections of the cortical column in field 17 in the cat].

The laminar structure of the cortical column connections in area 17 of the cat was studied using the microiontophoretic injection of the horseradish peroxidase. Following the enzyme injection in one column at different depths below the cortical surface the identification of morphological types of labelled neurons and the estimation of their localization were performed. When enzyme has been delivered in the whole depth of the column pyramidal neurons labelled were found in upper (I/III) and lower (V/VI) layers (ratio II;I). When the depth of enzyme injection exceeded the cortex width the cells in layer IV were labelled as well. The ratio between the quantity of cells labelled in upper and lower layers was preserved. (II; I). After the enzyme injection in the upper part of the column labelled cells were found mainly in the upper layers. It is concluded that the neurons of the column of have extensive (up to 5 mm), predominantly horizontal afferent connections with the cells in upper and lower layers while the connections with neurons in layer IV are local and do not extend beyond 0.5 mm.

Afferent Pathways↗
PubMed1996

[The adaptation-protective effect of corticosteroids on the rat gastric mucosa and its mechanism].

The influence of stress-induced corticosteroid production on gastric ulceration, blood flow velocity in gastric microvessels and blood pressure was studied in rats. The role of plasma corticosteroids was investigated by means of blockade of the pituitary-adrenocortical system (PACS) and following corticosterone replacement therapy (400 mu/100 g b.w.). The blockade which was induced by Fi. hydrocortisone administration (7 days before stress, 30 mg/100 g b. w.) resulted in an insufficient corticosteroid production. To evaluate the influence of corticosteroids on blood flow velocity in gastric microvessels of muscular, submucosal and mucosal coats it was used intravital microfilming by means of a dark-field contact epiobjective. Stress (water immersion + restraint) induces an ulceration, a decrease in the systemic arterial blood pressure (3 h after stress onset) and a decrease in blood flow velocity in the gastric microvessels (3 h after stress onset). In rats with insufficient corticosteroid production stress-induced ulceration, a decrease in blood pressure and gastric blood velocity were more greater than in rats with intact PACS. Replacement corticosterone therapy corrected all parameters. The results revealed that antiulcerogenic effect of stress-induced glucocorticoid production is realised owing to normalisation of gastric blood supply which is provided by an increase in systemic blood pressure.

Adaptation, Physiological↗
PubMed1996

[The significance of the vascularization of embryonic donor brain for the viability of intraocular transplants in the rat].

Telencephalic regions of rat embryonic brain were transplanted into the adult rat eye anterior chamber on E12 and E14 stages of development. These stages fall on the onset of the vascularization and the presence of the well developed vascular network in the embryonic brain. After a month of cultivation E14 transplants were much more viable than E12 (appropriately 58% and 15%). Only few E12 grafts had no initial vascularization. These transplants displayed growth retardation, while differentiated neurons could be seen only on their periphery. The results of the investigation demonstrate the meaning of vascularization extent in donor embryonic nervous tissue in its survival in conditions of transplantation into the rat eye anterior chamber.

Animals↗
PubMed1996

[The asymmetry of the intrinsic connections of the cat striate cortex in the projection zone of the central visual field].

Spatial distribution of intrinsic connections in the visual field centre projection zone of the cat striate cortex, was investigated. Retrogradely labelled cells formed an oblong area and were found in superficial as well as deep cortical layers. The labelled cells were located mostly medially to the column under study. The revealed asymmetry shows that the orientation column cells have more extended connections with cells representing the visual field periphery. We suppose that the "silent" regions are asymmetrically located in respect to the orientation column cells' receptive fields. This can account for the influence of the visual field periphery.

Animals↗
PubMed1995

[The effect of the destruction of the striate and prestriate cortices on the differentiation of visual images in cats].

The experiments to examine the effects of different visual cortical lesions (area 17 and 21 of the cat cortex) on the image discrimination were conducted. Different image complexity and context of images presentation were established. Cats with area 17 lesion easily discriminated simple objects, and learned only positive image from context. Cats with area 21 lesion learned all experimental conditions. We suggest that intact area 21 carry out selection one object context.

Animals↗