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Injected inositol 1,4,5‐trisphosphate activates Ca 2+ ‐sensitive K + channels in the plasmalemma of Eremosphaera viridis
Author(s) -
Förster Birgit
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81153-f
Subject(s) - intracellular , inositol , cytoplasm , biophysics , chemistry , bapta , inositol trisphosphate , conductance , biochemistry , biology , receptor , mathematics , combinatorics
InsP 3 , an established mediator of intracellular Ca 2+ signals in animal cells, is microinjected into the cytoplasm of Eremosphaera viridis . InsP 3 , but not Ins, InsP 1 , InsP 2 or F2,6‐P 2 induce a transient opening of Ca 2+ ‐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 TMB 8 (2 mM), an intracellular Ca 2+ antagonist or by BAPTA (20 mM), microinjected together with InsP 3 . The results suggest that InsP 3 initiates an increase in the cytoplasmic Ca 2+ activity and an activation of Ca 2+ ‐dependent membrane currents, hence, opening of K + channels.