Demonstration of the K+ channel in the plasmalemma of tonoplast-free cells of Chara australis.
Tonoplast-free and ATP-less internodal cells of Chara australis were made by perfusing cells internally with a medium containing ethyleneglycol-bis-(β-aminoethylether) N, N'-tetraacetic acid, hexokinase and glucose. Such a cell showed rapid light-induced potential change when it was stained with neutral red (5). The rapid light-induced potential change was inhibited by tetraethylammonium, a known inhibitor of the K(+) channel in nerve cells. Tetraethylammonium acted both from the inside of the membrane and from the outside with similar effectiveness. Nonyltriethylammonium inhibited the light response far more effectively than did tetraethylammonium. The results suggest the existence of a K(+) channel which is activated by light in the Chara membrane.
Department of Botany, Faculty of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan.
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M
Tazawa
Department of Botany, Faculty of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan.
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T
Shimmen
Chara; K+-channel; Membrane potential; Tetraethylammonium; Tonoplast-free cell