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Calcium channel antagonists induce direct inhibition of the outward rectifying potassium channel in tobacco protoplasts
Author(s) -
Thomine Sébastien,
Zimmermann Sabine,
Van Duijn Bert,
Barbier-Brygoo Hélène,
Guern Jean
Publication year - 1994
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(94)80170-3
Subject(s) - bepridil , verapamil , potassium channel , nicotiana tabacum , biophysics , calcium , calcium channel , potassium , chemistry , potassium channel blocker , calcium activated potassium channel , membrane potential , voltage dependent calcium channel , nifedipine , biology , biochemistry , organic chemistry , gene
Verapamil, nifedipine and bepridil, three antagonists of L‐type calcium channels in animal cells, were shown to induce direct inhibition of outward rectifying potassium current in Nicotiana tabacum cv. Xanthi protoplasts with IC 50 of 5 μM, 5 μM and 1 μM, respectively. In the outside‐out configuration, verapamil reduced the open probability of the ion channel responsible for the outward rectifying potassium conductance. Verapamil also blocked the outward rectifying potassium conductance in protoplasts from the N. tabacum cv. Bright Yellow cell line. Thus, studies using these molecules to demonstrate the involvement of calcium channels in plant physiological responses should be regarded with caution.