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Titolo:
Effect of osmotic stress on potassium accumulation around glial cells and extracellular space volume in rat spinal cord slices
Autore:
Vargova, L; Chvatal, A; Anderova, M; Kubinova, S; Ziak, D; Sykova, E;
Indirizzi:
Acad Sci Czech Republ, Inst Expt Med, Dept Neurosci, Prague 14220 4, CzechRepublic Acad Sci Czech Republ Prague Czech Republic 14220 4 220 4, CzechRepublic Charles Univ, Dept Neurosci, Fac Med 2, Prague, Czech Republic Charles Univ Prague Czech Republic i, Fac Med 2, Prague, Czech Republic Charles Univ, Ctr Cell Therapy & Tissue Repair, Prague, Czech Republic Charles Univ Prague Czech Republic issue Repair, Prague, Czech Republic
Titolo Testata:
JOURNAL OF NEUROSCIENCE RESEARCH
fascicolo: 2, volume: 65, anno: 2001,
pagine: 129 - 138
SICI:
0360-4012(20010715)65:2<129:EOOSOP>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
MEMBRANE CURRENT PATTERN; SWELLING-INDUCED CHANGES; ELECTROPHYSIOLOGICAL PROPERTIES; CULTURED ASTROCYTES; WHITE-MATTER; OLIGODENDROCYTES; MORPHOLOGY; TORTUOSITY; FRACTION; ION;
Keywords:
astrocytes; diffusion; ECS volume fraction; extracellular space; hyperosmotic solution; hypoosmotic solution; oligodendrocytes; potassium tail currents;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
41
Recensione:
Indirizzi per estratti:
Indirizzo: Chvatal, A Acad Sci Czech Republ, Inst Expt Med, Dept Neurosci, Videnska 1083, Prague14220 4, Czech Republic Acad Sci Czech Republ Videnska 1083 Prague Czech Republic 14220 4
Citazione:
L. Vargova et al., "Effect of osmotic stress on potassium accumulation around glial cells and extracellular space volume in rat spinal cord slices", J NEUROSC R, 65(2), 2001, pp. 129-138

Abstract

in rat brain and spinal cord slices, the local extracellular accumulation of K+, as indicated by K+ tail currents (I-tail) after a depolarization step, is greater in the vicinity of oligodendrocytes than that of astrocytes, It has been suggested that this may reflect a smaller extracellular space (ECS) around oligodendrocytes compared to astrocytes (Chvatal et al, [1997] J, Neurosci, Res. 49:98-106; [1999] J. Neurosci, Res. 56,493-505). We therefore compared the effect of osmotic stress in spinal cord slices from 5-11-day-old rats on the changes in reversal potentials (V-rev) of I-tail measured by the whole-cell patch-clamp technique and the changes in ECS volume measured by the real-time iontophoretic method. Cell swelling induced by a 20min perfusion of hypoosmotic solution (200 mmol/kg) decreased the ECS volume fraction from 0.21 +/- 0.01 to 0.15 +/- 0.02, i.e., by 29%, As calculated from V-rev of I-tail using the Nernst equation, a depolarizing prepulse increased [K+](e) around astrocytes from 11.0 to 44.7 mM, i.e., by 306%, andaround oligodendrocytes from 26.1 to 54.9 mM, i.e., by 110%. The ECS volume fraction decrease had the same time course as the changes in V-rev of I-tail. Cell shrinkage in hyperosmotic solution (400 mmol/kg) increased ECS volume fraction from 0.24 +/- 0.02 to 0.32 +/- 0.02, i.e., by 33%, It had no effect on [K+](e) evoked by a depolarizing prepulse in astrocytes, whereas in oligodendrocytes [K+](e) rapidly decreased from 52 to 26 mM, i.e., by 50%, The increase in ECS volume was slower than the changes in [K+](e). Thesedata demonstrate that hypoosmotic solution has a larger effect on the ECS volume around astrocytes than around oligodendrocytes and that hyperosmoticsolution affects the ECS volume around oligodendrocytes only. This indicates that increased K+ accumulation in the vicinity of oligodendrocytes couldbe due to a restricted ECS, Oligodendrocytes in the CNS are therefore mostlikely surrounded by clusters of "compacted" ECS, which may selectively affect the diffusion of neuroactive substances in specific areas and directions and facilitate spatial K+ buffering. (C) 2001 Wiley-Liss, Inc.

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Documento generato il 06/07/20 alle ore 05:37:32