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J Membr Biol. 2000 May 15;175(2):87-93.

Effects of Na(+) on the predominant K(+) channel in the tonoplast of Chara: decrease of conductance by blocks in 100 nanosecond range and induction of oligo- or poly-subconductance gating modes.

Author information

1
Abteilung Biophysik der Pflanze, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Universität Göttingen, Untere Karspüle 2, D-37073 Göttingen, Germany.

Abstract

We present three mechanisms by which Na(+) inhibits the open channel currents of the predominant K(+) channel in the tonoplast of Chara corallina: (i) Fast block, i.e., short (100 ns range) interruptions of the open channel current which are determined by open channel noise analysis, (ii): Oligo-subconductance mode, i.e., a gating mode which occurs preferentially in the presence of Na(+); this mode comprises a discrete number (here 3) of open states with smaller conductances than normal, and (iii): Polysubconductance mode, i.e., a gating mode with a nondiscrete, large number (>30) of states with smaller conductances than the main open channel conductance. This novel mode has also been observed only in the presence of Na(+).

PMID:
10811970
[Indexed for MEDLINE]

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