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V K Uteshev

Publications and source records attributed to V K Uteshev.

At least 19 recordsLinked to original sources
PubMed2002

Mechanisms of amnestic effect of ergot alkaloid agroclavin.

Neurochemical mechanisms of the effect of agroclavin on spatial memory in the Morris water maze in mice were studied by analyzing the effect of neurotransmitter receptor ligands on the amnestic effect of this alkaloid. D1-receptor agonist SKF-38393 and calcium channel blockers verapamil and nimodipine abolished the negative effect of agroclavin on spatial memory. The role of intracellular calcium in the mechanisms of amnestic effect of agroclavin is discussed.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed2000

[The reaction of endoplasmic reticulum of Mauthner cells of Xenopus laevis tadpoles in response to the partial denervation].

The structure of the Mauthner cells in Xenopus laevis tadpole was investigated by light- and electron microscopy in norm and after early unilateral enucleation. It was found that enucleation at early stages caused a delay in morphological development of the contralateral neurons during embryogenesis. We observed a decrease in size of the soma and nucleus and in the number of dendrites, a marked structural underdevelopment of the majority of cell organoids, as well as proliferation and hypertrophy of transversal cisternae in the contralateral Mauthner cells. The ipsilateral neurostructure remained normal in embryogenesis. The data obtained suggest the availability of some unknown powerful afferent contralateral input to Mauthner cells from the optical analyzer.

Animals↗
PubMed1999

[Morphogenesis of Mauthner neurons of Xenopus laevis tadpoles following early unilateral eye enucleation].

The connection between Mauthner neuron (CMN) and visual analyzer in Xenopus laevis tadpoles was studied using these neurons capacity to change their morphogenesis during the development in case of interruption of their connections with afferent fibres. In phase 31 of development tadpoles were subjected to unilateral enucleation of eye. Morphogenesis of contralateral (experimental) and ipsilateral (control) MN with respect to the operated eye was followed up. Comparison with intact Mauthner neuron of the tadpole of the same age who were not exposed to operation was conducted. Contralateral MN were found to be delayed in development phases 47 and 50. This was associated with 1.5-3.3 fold difference in neuron body central section area and 2-3 fold differences in nuclear section area. Three-dimensional reconstruction revealed lower number of cell processes in contralateral MN as well as decline in their length and diameter. Control and intact MN showed no difference similar to experimental and control ones in phase 41. The data obtained indicate that MN of Xenopus laevis tadpole possess powerful ipsilateral connections originating from the side of visual analyzer and contralateral ones from the side of the eye. This affects MN development and in contrast to octavolateral system (including vestibular apparatus and organs of lateral line) controls the contralateral neuron.

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PubMedDate not supplied

Dimensions of the hippocampus, memory, and learning in the ontogenesis of rats.

Damage to the hippocampus in 20-, 50-, and 110-day-old rats impairs the processes of learning and short-term memory in them. In 50-day-old rats, hippocampectomy has less of an influence on the process of learning and memory than for 20- and 110-day-old animals. The anatomic and physiological characteristics of the hippocampus in 20-day-old rats may be evidence of a special importance of this formation at the early stages of ontogenesis, when the cerebral cortex is still insufficiently mature and its associations with other structures have not been entirely formed. The nonlinear nature of the dependence of the disruption of learning in rats of different ages after hippocampectomy suggests that the function of the rat hippocampus undergoes changes during the process of individual development of the animal.

Age Factors↗
PubMedDate not supplied

[The wave-like character of the defence conditioned reflex acquisition in rats].

The dynamic peculiarities of formation of conditioned avoidance in rats were studied during 15-day sessions using different experimental paradigms (massed and spaced training). In all the experimental situations, the acquisition curves were wave-like (independently of the paradigm). Regression curves of the 6th or 7th order most perfectly fit the experimental data, which suggests that the acquisition dynamics in both paradigms is non-linear.

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PubMedDate not supplied

[Fluorescent analysis of cryopreserved totipotent cells of amphibian embryos].

The cryotolerance of totipotent cells from dissociated embryos of amphibian (grass frog Rana temporaria and grey toad Bufo bufo) was studied. Cell integrity and preservation of the cell barrier function were evaluated by fluorescent analysis. It was shown that the best cryopreservation of the cells was achieved by using the cryoprotective agent 10% dimethyl sulfoxide and 10% saccharose. These cells were successfully used for the homotransplantation of nuclei into enucleated eggs. The development of reconstructed eggs to the blastula stage was noted.

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PubMedDate not supplied

[The role of lipid-nucleic acid interactions in the reconstruction in vitro of the nuclear shell with pores].

Previous studies of triple complexes DNA-phosphatidylcholine liposomes-Me2+ showed that, upon complexing, along with aggregation, a partial reversible fusion of liposomes takes place. In this case, DNA acts as a fusogen. The addition of the extract from Xenopus laevis or Drosophila melanogaster oocytes to the triple complex leads to a complete fusion of initial liposomes 100-200 nm in size and the formation of giant liposomes of up to 100-500 microns in size. Upon the addition of liposomes to the extract from Xenopus or Drosophila eggs, either fragments of the nuclear envelope with pores or structures like annulate lamellae are formed. The diameter of pores in these formations is approximately twice as small as in the native nuclear envelope, which may be associated with a lower surface tension of the lipid bilayer. This fact is in agreement with our model of the formation of nuclear pores suggested earlier.

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PubMedDate not supplied

[Changes in the permeability of amphibian embryo envelope for fluorochromes under the action of ultrasound].

It was determined whether high-frequency ultra sound can change the permeability of gray toad Bufo bufo and grass frog Rana temporaria under the action of high-frequency ultrasound. The changes in the permeability of embryonic envelope were assessed by using slowly penetrating fluorochromes ANS, FDA, and fluorescein. It was found that the ultrasound of 0.88 MHz and 0.4 - 0.7 W/cm2 intensity increased the permeability of amphibian embryonic envelope for ANS and FDA, whereas the ultrasound of 2.64 MHz and the same intensity increased that for fluorescein with the retention of low permeability for FDA. Embryos continued the normal development after treatment with ultrasound under these conditions.

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PubMedDate not supplied

[Survival of amphibian embryos after continuous ultrasound treatment].

The influence of continuous ultrasound on the embryonic development of grass frog Rana temporaria has been investigated. Intact embryos at the blastula stage were treated by ultrasound of different frequency (0.88 and 2.64 MHz), intensity (0.05-1.0 W/cm2), and duration (1-15 min). The treatment with ultrasound of frequency 0.88 MHz and intensity 0.05 W/cm2 for 1-5 min tended to increase the proportion of normally developing embryos up to hatch (10-25% of control). Increasing the intensity of ultrasound (0.88 MHz) to 0.7-1.0 W/cm2 and the duration of its action to 5-15 min induced the death of almost all of treated embryos. No significant differences were found between the development of control embryos and embryos treated with ultrasound of middle intensity (0.2-0.7 W/cm2) for 1-5 min. The exposure of amphibian embryos to ultrasound of frequency 2.64 MHz and intensity 0.05-0.7 W/cm2 for 1-5 min did not change their survival. Increasing the intensity of ultrasound (2.64 MHz) to 1.0 W/cm2 and the duration of its action to 5 min decreased the number of normal developing embryos (by 35%).

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PubMedDate not supplied

[Efficacy of repeated training at different stages of elaboration of a defensive reflex in the mouse].

It has been found that the efficiency of additional learning is in no linear dependency on interval value between initial and repeated conditioning sessions. At consecutive interval extension the efficiency of additional session changes wave-like. The effect of repeated learning session directly correlates with successful reproduction of traces of initial reflex elaboration in the second session. It is suggested that fluctuations of reproduction of unstable reflexes and of efficiency of additional learning sessions depend on changes in spatial relations of bioelectrical processes in the cortex which accompany the additional learning.

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