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Titolo:
Anoxic decrease in potassium outward currents of hippocampal cultured neurons in absence and presence of dithionite
Autore:
Gebhardt, E; Heinemann, U;
Indirizzi:
Humboldt Univ, Inst Physiol, D-10117 Berlin, Germany Humboldt Univ Berlin Germany D-10117 st Physiol, D-10117 Berlin, Germany
Titolo Testata:
BRAIN RESEARCH
fascicolo: 1-2, volume: 837, anno: 1999,
pagine: 270 - 276
SICI:
0006-8993(19990807)837:1-2<270:ADIPOC>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAT CENTRAL NEURONS; IN-VITRO; CA1 NEURONS; HYPOXIC HYPERPOLARIZATION; DEPRIVATION; CHANNELS; ADULT; CELLS; PHOSPHORESCENCE; MECHANISMS;
Keywords:
hypoxia; potassium currents; hippocampal neurons; oxygen measurements; hydrosulphite;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
30
Recensione:
Indirizzi per estratti:
Indirizzo: Gebhardt, E Humboldt Univ, Inst Physiol, Tucholskystr 2, D-10117 Berlin, Germany Humboldt Univ Tucholskystr 2 Berlin Germany D-10117 , Germany
Citazione:
E. Gebhardt e U. Heinemann, "Anoxic decrease in potassium outward currents of hippocampal cultured neurons in absence and presence of dithionite", BRAIN RES, 837(1-2), 1999, pp. 270-276

Abstract

The effect of brief anoxia on voltage dependent Kc-currents of hippocampalcultured neurons was studied. The oxygen scavenger dithionite (hydrosulphite) was previously used for creating zero oxygen pressure. However, dithionite consumes OZ in parallel with generation of superoxide radicals and is astrongly reducing agent. In this study anoxia was produced by perfusion ofthe neurons with a solution bubbled with nitrogen for 1 h using a chamber with an argon layer isolating the anoxic bath flow from atmospheric oxygen in presence and absence of dithionite. Oxygen partial pressure of dithionite-free solution was determined by oxygen dependent quenching of the phosphorescence of Pd-coproporphyrin to be 0.15 +/- 0.02 Torr (values are given asmean +/- S.D., n = 6). Slow (IK)I-K and fast (I,)-inactivating K+-currentswere measured with the patch clamp technique in the whole cell configuration. Exposure of the neurons to anoxia reversibly decreased the amplitude ofI-K at a test pulse of 0 mV to 77 +/- 12% (a = 7) in absence and to 83 +/-7% (n = 6) in presence of 2 mM dithionite; the amplitude of I, decreased to 78 +/- 11% in absence and to 82 +/- 9% in presence of 2 mM dithionite. Voltage dependence of activation and inactivation shifted 5 min after exposure to anoxia reversibly by about 6 mV in depolarizing direction. The decay times of inactivation were insensitive to anoxia. Dithionite had no significant effects on K+-currents. In 15 of 21 neurons not employed for analysis on K+-cunrents, a reversible increase in holding current under dithionite was observed. In absence of dithionite in 4 of 19 neurons the holding currentreversibly increased during anoxia. Although dithionite does not affect K+-currents, changes in holding current show that the dithionite may affect neurons independently of oxygen deprivation. (C) 19951 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 14/07/20 alle ore 09:01:53