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Biomedical subjects

A Iu Budantsev

Publications and source records attributed to A Iu Budantsev.

At least 19 recordsLinked to original sources

[Computer-assisted 3-D reconstruction of biological objects using serial sections].

In this review, the literature data on the major directions and problems of experimental technology of "3-D Histology", based on the analysis of serial sections, are discussed. The main attention is drawn to the principle problem: achievement of realness (accuracy) of generated 3-D models, i. e. to the problem of correspondence of native tissue structure to its computer 3-D model. The review consecutively presents the possible sources of distortions which accompany the researchers during 3-D modeling. The artifacts are considered which arise at a stage of computer 3-D modeling on the basis of serial histological sections of investigated structures. The special attention is given to distortion of the native tissue morphology during histological processings in the course of preparation of serial sections. The aspects and problems discussed in this review, are important for the transition from 3-D tissue reconstruction to 3-D histology.

Animals↗

[The role of the adenyl cyclase system in cholinergic modulation of synaptic transmission in the hippocampus].

The adenylate cyclase system has been studied from the standpoint of its significance in cholinergic modulation of the synaptic transmission in the CA1 field of the rat hippocampal slices. Microionphoretic application of ACh as well as addition of either carbachol or tolbutamide (an inhibitor of cAMP-dependent protein kinase) blocked the transmission in synapses formed by the Schaffer collaterals and commissural fibres with dendrites of carbacholine both the number of releasing quanta of the neurotransmitter and the probability of their release decreased. Atropine eliminated the inhibitory effect of carbacholine on synaptic transmission. Dibutyryl cAMP and forskolin increased the amplitude of synaptic potentials and completely or partially prevented the inhibitory effect of cholinomimetics on synaptic potentials. The results obtained revealed opposite effects of cholinomimetics and activators of the adenylate cyclase system on neurotransmission in synapses formed by the Schaffer collaterals/commissural fibres and dendrites of pyramidal neurons of the hippocampal CA1 field.

Acetylcholine↗

[Role of cyclic AMP in the action of dopamine on the spontaneous and glutamate-induced activity of neostriatal neurons in the rat].

The influence of microionophoretically applied dopamine and dibutyril cAMP on the background and glutamate-evoked spike activity of neostriatum neurons was studied in acute experiments on rats immobilized by d-tubocurarine. The mean rate, stationarity, interspike interval histograms and autocorrelation functions for extracellularly recorded spike activity were measured. It was shown that dibutyril cAMP imitated the inhibiting dopamine effect on the background and glutamate-evoked spike activity of neostriatum neurons rather than the stimulating effect.

Animals↗

[Electron microscopic study of the monoaminergic terminals in the caudate nucleus of the rat brain].

A comparative analysis of some electron-microscopic techniques has been carried out to reveal biogenous amines in the rat muscle nucleus caudatus. Monoaminergic terminals were identified by the presence of large and small granular vesicles. The best results were obtained by chromaffine reaction of frozen sections: the revealing of small granular vesicles by this method is 11 fold more effective than that by the use of chromaffine reaction carried out on tissue samples.

Animals↗

[Influence of septo-hippocampal pathway deafferentation on multiple forms of acetylcholinesterase in fascia dentata in the Rabbit].

Electrophoresis separation of membrane acetylcholinesterase in 5% PAAG resulted in five forms of the enzyme differing by electrophoretic mobility and velocity of ACh hydrolysis. The activity of isoforms (I, II) was decreased by 40 and 76, respectively, 4 days after deafferentiation of septo-hippocampal pathways. Changes in the activity were still greater 7 days after deafferentiation as compared with those mentioned above.

Acetylcholinesterase↗

[Effect of beta-phenylethylamine on the dopaminergic system of rat brain].

Using a quantitative fluorescence-histochemical analysis the dynamics of changes of the dopamine level in dopaminergic neurons of the nigro-neostriatal and mesolimbic systems of the rat brain was studied during an hour after intraperitoneal injection of beta-phenylethylamine (100 mg/kg). The temporary increase in the dopamine level in the terminals coincided with a sharp decrease in the dopamine level in the neuron bodies, and conversely, the depletion of dopamine in the terminals after 30 min was accompanied by an increase in the dopamine level in the neuron bodies. The obtained results enable a suggestion that the increase in locomotor activity of animals after injection of beta-phenylethylamine described in the literature is due to the effect of phenylethylamine on catecholaminergic brain systems, the dopaminergic systems in particular.

Animals↗

[Quantitative histochemical study of monoamine oxidase in the rabbit hippocampal formation].

Distribution of monoamine oxidase (MAO) in the rabbit hippocampal formation was studied using the quantitative histochemical methods. Specific reduction of the nitro-blue tetrazolium was observed in the str. lacunosum-moleculare of hippocampal fields CA1 and CA2 and in str. moleculare of the fascia dentata. There is a large number of myelinated fibres in stratum alveus and Shaffer's collaterals with strong positive reaction. However, large amounts of diformazan were found in this stratum after incubation without a substrate. This and other data on spontaneous reduction of nitro-blue tetrazolium by myelin allow considering that the positive reaction of Glenner in alveus and collateralis of Shaffer is nonspecific. The diformazan in the str. pyramidale and str. granulare is nonspecific too, which was confirmed by preincubation in iproniazide and incubation without a substrate.

Animals↗

[Distribution of biogenic amines in the hippocampal formation in the rabbit].

The hippocampal formation (the hippocampus and the dentate fascia) of the rabbit was studied by histochemical fluorescent method of Falk to determine localization of monoaminergic terminals containing biogenic amines: noradrenalin, dophamine and serotonin. It was shown that monoaminenergic terminals in the hippocampus were in two zones of afferent terminations: in the zone of ending of the perforating way (str. lacunosum-moleculare of fields CA1 and CA2; str. moleculare of the dentate fascia) and in the subgranular zone of the hilum where a part of septofimbrial way terminated on granular neurons of the dentate fascia, the main cellular elements of the hipocampus (pyramidal, granular and basket cells of the hippocampus) did not contain biogenic amines.

Animals↗

[Zinc-iodine-osmium impregnation of giant synaptosomes obtained from the hippocampal formation of the rabbit].

The fraction of giant synaptosomes from the r. inferior of the rabbit hippocampus was studied using impregnation with zinc iodide-osmium tetroxide (XIO) reagent and electron microscopy. In this fraction, light and dark synaptosomes were observed. The reaction product was found in the clear-centered synaptic vesicles (200-400 A) as electron-dense structures of different forms and small osmiophilic particles on the vesicular membranes. Dense-cored vesicles and postsynaptic structures were not revealed with ZIO-reagent. The structures revealed with ZIO-reagent in the giant synaptosomes of the hippocampus are supposedly related to stroage of the neurotransmitter-glutamate.

Animals↗

[Distribution of biogenic amines and acetylcholinesterase in the mammillary nuclei of rabbits].

The distribution of biogenic amines (BA) and acetylcholinesterase (AChE) in mamillary nuclei of rabbits was studied by the methods of Falck, Karnovski and Roots. The general mass of BA was shown to localize in the terminals of the lateral mamillary nucleus and in the supramamillary area. The amount of BA-terminals in the medial nucleus is insignificant. Besides, the cells containing BA were found in the lateral part of the lateral nucleus. AChE is localized mainly in the neuropile and the cells of the medical nucleus and the cells of the lateral mamillary nucleus. The fornix and the mamillo-thalamic tract do not respond to AChE (poor activity in the mamillo-thalamic tract) and to BA. The obtained results suggest the afferents of the medial nucleus to be cholinergic, and those of the lateral nucleus - monoaminergic. Due to the presence of AChE-cells in the medial nucleus and BA-cells and AChE-cells in the lateral nucleus a supposition is possible that while the afferents of the nedial nucleus are cholinergic, the efferents of the lateral nucleus contain both AChE AND BA.

Acetylcholinesterase↗