Search

Your search keyword '"Tikhonov, D B"' showing total 159 results
Start Over Author "Tikhonov, D B"
159 results on '"Tikhonov, D B"'

4. Erratum to: The original online version of the following articles was revised: the issue date is not January 2020, but January 2021

Author

Spirov, A. V., Levchenko, V. F., Sabirov, M. A., Grigorev, I. P., Korzhevskii, D. E., Evsyukova, I. I., Lunichkin, A. M., Zhukovskaya, M. I., Gorshkova, O. P., Silkin, Yu. A., Silkina, E. N., Silkin, M. Yu., Ravaeva, M. Yu., Chuyan, E. N., Cheretaev, I. V., Mironyuk, I. S., Grishina, T. V., Pushchina, E. V., Kapustyanov, I. A., Shamshurina, E. V., Varaksin, A. A., Fedorova, I. M., Tikhonov, D. B., Prutskova, N. P., Seliverstova, E. V., Hernandez-Cortes, P., Ünüvar, S., Gürsoy, Ş., Berk, A., Kaymaz, B., İlhan, N., Aktay, G., El-Kafoury, B. M. A., Saad, R. A., Ismail, E. G. M., Abdel-Hady, E. A., Lobov, G. I., Ivanova, G. T., Plekanchuk, V. S., Ryazanova, M. A., Pogorelova, T. N., Gunko, V. O., Nikashina, A. A., and Alliluev, I. A.

Published
2021
Full Text
View/download PDF

43. Voltage-dependent block of native AMPA receptor channels by dicationic compounds

Author

Tikhonov, D. B., Samoilova, M. V., Buldakova, S. L., Gmiro, V. E., and Lev Magazanik

Subjects
Kainic Acid, Patch-Clamp Techniques, musculoskeletal, neural, and ocular physiology, Pyramidal Cells, Adamantane, Diamines, Hippocampus, Membrane Potentials, Rats, Electrophysiology, Quaternary Ammonium Compounds, Kinetics, nervous system, Cations, Papers, Excitatory Amino Acid Agonists, Animals, Receptors, AMPA
Abstract

1. The kinetics of open channel block of GluR2-containing and GluR2-lacking AMPA receptors (AMPAR) by dicationic compounds (IEM-1460, IEM-1754, and IEM-1925) have been studied in rat hippocampal neurones using whole-cell patch clamp recording and concentration-jump techniques. Neurones were isolated from hippocampal slices by vibrodissociation. 2. The dicationic compounds were approximately 100 - 200 times more potent as blockers of GluR2-lacking AMPAR than as blockers of GluR2-containing AMPAR. The subunit specificity of channel block is determined by the blocking rate constant of a dicationic compound, whereas differences in unblocking rate constants account for differences in potency. 3. Hyperpolarization may decrease the block produced by IEM-1460 and IEM-1754 block due to the voltage-dependence of the unblocking rate constants for these compounds. This suggests that dicationic compounds permeate the AMPAR channel at negative membrane potentials. The effect was particularly apparent for GluR2-lacking AMPAR. These findings indicate that the presence of GluR2-subunit(s) in AMPAR hinders the binding of the cationic compounds and their permeation through the channel. 4. The most potent compound tested was IEM-1925. The presence of a phenylcyclohexyl moiety instead of an adamantane moiety, as in IEM-1460 and IEM1754, is probably responsible for the higher potency of IEM-1925. Dicationic compounds are important not only as pharmacological tools, but also as templates for the synthesis of new selective AMPAR blockers which may be potential therapeutic agents.

Published
2000

49. Architecture of the neuronal nicotinic acetylcholine receptor ion channel at the binding site of bis-ammonium blockers.

Author

Brovtsyna, N B, Tikhonov, D B, Gorbunova, O B, Gmiro, V E, Serduk, S E, Lukomskaya, N Y, Magazanik, L G, and Zhorov, B S

Abstract

Structure-activity relationships of 56 pentamethylenbis-ammonium compounds, the blockers of the neuronal nicotinic acetylcholine receptor (nAChR) ion channel, have been studied to estimate the cross-sectional dimensions of the channel pore. The cat superior cervical sympathetic ganglion in situ and isolated guinea pig ileum were used to evaluate the potency of the compounds to block ganglionic transmission. Minimum-energy conformations of each compound were calculated by the molecular mechanics method. A topographic model of the binding site of the blockers was proposed. It incorporates two narrowings, a large and a small one. The small narrowing is located between the large one and the cytoplasmic end of the pore. The cross-sectional dimensions of the large and small narrowings estimated from the dimensions of the blockers are 6.1 x 8.3 A and 5.5 x 6.4 A, respectively, the distance between the narrowings along the pore being approximately 7 A. Most potent blockers would occlude the pore via binding to the channel at the levels of both narrowings. Less potent blockers are either too large or too small to bind to both narrowings simultaneously: large blockers would occlude the pore at the level of large narrowing, while small blockers would pass the large narrowing and occlude the pore at the level of small narrowing only. A comparison of the topographic model with a molecular five-helix bundle model of nAChR pore predicts Serine and Threonine rings to be the most probable candidates for the large and small narrowings, respectively. [ABSTRACT FROM AUTHOR]

Published
1996

50. Ca2dependent desensitization of AMPA receptors

Author

Buldakova, S L., Bolshakov, K V., Tikhonov, D B., and Magazanik, L G.

Abstract

The effect of changes in the external concentrations (0.4-10 mM) of Ca2ions on AMPA receptors (AMPARs) of different subunit composition was studied on freshly isolated rat brain neurones. Ca2produces rapid and reversible voltage-independent inhibition of AMPARs. Ca2-permeable and Ca2-impermeable AMPARs are equally sensitive to external Ca2suggesting that the effect is not addressed to the ion channel. The inhibition of responses evoked by AMPA is significantly larger than those evoked by kainate or glutamate. Cyclothiazide and aniracetam, which are known to prevent AMPAR desensitization, both greatly diminish inhibition of AMPARs by Ca2. Cyclothiazide is more potent than aniracetam in both preventing of AMPAR desensitization and protecting against the Ca2inhibitory effect on hippocampal pyramidal cells. On giant cholinergic interneurones of striatum, aniracetam but not cyclothiazide significantly prevents inhibition by Ca2. This agrees with available data on relative abundance of flip and flop splice variants in these cell types. The results suggest that Ca2may allosterically increase AMPA receptor desensitization independently on subunit composition and splice variants.

Published
2000

Catalog

Books, media, physical & digital resources
See catalog results