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The role of desensititation in decay time of miniature endplate currents in frogs Rana ridibunda and Rana temporaria
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SYSNO ASEP 0142139 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Ostatní články Title The role of desensititation in decay time of miniature endplate currents in frogs Rana ridibunda and Rana temporaria Author(s) Giniatullin, R. A. (CZ)
Talantova, M. V. (CZ)
Vyskočil, František (FGU-C) RIDSource Title Neuroscience Research. - : Elsevier - ISSN 0168-0102
Roč. 39, č. 3 (2001), s. 287-292Number of pages 6 s. Language eng - English Country IE - Ireland Keywords frog ; desensitisation ; miniature endplate potential Subject RIV ED - Physiology R&D Projects IAA7011902 GA AV ČR - Academy of Sciences of the Czech Republic (AV ČR) VS97099 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) OK 267 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) CEZ AV0Z5011922 - FGU-C Annotation A new comparative characteristic of endplate microphysiology has been introduced. It is the feasibility of receptors to become desensitised as demonstrated on two frog species, Rana temporaria and Rana ridibunda: the decay times (tau(MEPC)) of single quantum miniature endplate currents (MEPCs) in the sartorius muscles of both species were about 1 ms and were not affected by the desensitisation-promoting agent proadifen when AChE was active. However, when the desensitisation was induced by anticholinesterase neostigmine and promoted by proadifen, the prolongation of tau(MEPC) from 1 ms was almost twice as great in Rana temporaria (tau(MEPC) = 4.4 ms) than in Rana ridibunda (tau(MEPC) = 3.1). This indicates that desensitisation reduces the number of available receptors and lowers the number of available ACh molecules for repetitive binding by trapping them by desensitised, high-affinity receptors significantly more in Rana ridibunda than in Rana temporaria. The application of proadifen, a promoter of desensitisation, decreased the prolongation of MEPCs in both species, but this shortening was more rapid in Rana ridibunda than in Rana temporaria. It is concluded that the desensitisation-induced reduction in the density, and the number of postsynaptic receptors is significantly higher at Rana ridibunda than in Rana temporaria endplates. Workplace Institute of Physiology Contact Lucie Trajhanová, lucie.trajhanova@fgu.cas.cz, Tel.: 241 062 400 Year of Publishing 2002
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