Injected inositol 1,4,5‐trisphosphate activates Ca2+ ‐sensitive K + channels in the plasmalemma of Eremosphaera viridis

FEBS Letters

Förster, Birgit¹ 

[1]Botanisches Institut I, Universität Würzburg, Würzburg, FRG

关键词: InsP3;    K+ channel;    Ca2+ -dependent;    Transient potential;    Eremosphaera viridis;    BAPTA;    bis-(o-aminophenoxy)-ethane N;    N;    N';    N' tetraacetic acid;    E K;    Nernst potential of potassium;    E m;    membrane potential;    ER;    endoplasmic reticulum;    F2;    6-P2;    fructose 2;    6-bisphosphate;    Ins;    myo-inositol;    InsP1;    myo-inositol 2-monophosphate;    InsP2;    myo-inositol 1;    4-bisphosphate;    InsP3;    myo-inositol 1;    4;    5-trisphosphate;    TEA;    tetraethylammonium;    TMB8;    3;    4;    5-trimethoxybenzoic acid 8-diethylaminooctyl ester;    TP;    transient potential;   

DOI  :  10.1016/0014-5793(90)81153-F

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

InsP₃, an established mediator of intracellular Ca²⁺ signals in animal cells, is microinjected into the cytoplasm of Eremosphaera viridis. InsP₃, but not Ins, InsP₁, InsP₂ or F2,6-P₂ induce a transient opening of Ca²⁺ -dependent K⁺ channels in the plasmalemma of this alga. This effect is indicated by a transient polarization (TP) with a simultaneous increase of membrane conductance. The TP is inhibited by TMB₈ (2 mM), an intracellular Ca²⁺ antagonist or by BAPTA (20 mM), microinjected together with InsP₃. The results suggest that InsP₃ initiates an increase in the cytoplasmic Ca²⁺ activity and an activation of Ca²⁺-dependent membrane currents, hence, opening of K⁺ channels.

【 授权许可】

Unknown