Effect
of Ethanol on Tracheal Potassium Channels
Reconstituted into Bilayer Lipid Membranes
V.
KOMÍNKOVÁ, M. MAGOVÁ, A. MOJŽIŠOVÁ, Ľ.
MÁLEKOVÁ,
K. ONDRIAŠ
Institute
of Molecular Physiology and Genetics, Slovak
Academy of Sciences, Bratislava, Slovak Republic
Received November 21,
2000
Accepted February 20, 2001
Summary
We
examined the effect of ethanol on single
potassium channels derived from plasma membranes
of bovine tracheal smooth muscles. The observed
potassium channels had a conductance of 296±31
pS (mean ± S.D.) in symmetrical 250 mmol/l KCl
solutions, and exhibited a voltage- and
Ca2+-dependence similar to BKCa channels. Ethanol
at 50, 100 and 200 mM concentrations increased
the probability of open potassium channels to
112±5, 127±7 and 121±13% (mean ± S.E.M.),
respectively. It is suggested that increased
activity of the BKCa channels by ethanol
hyperpolarizes the plasma membrane and thus may
contribute to relaxation of tracheal smooth
muscle.
Key
words
Potassium
channel · Trachea - Ethanol · Bilayer lipid
membrane · Bronchodilation
Reprint
requests
Dr.
Karol Ondriaš, Institute of Molecular Physiology
and Genetics, Slovak Academy of Sciences,
Vlárska 5, 833 34 Bratislava, Slovak Republic,
fax.: +421-7-54773666, e-mail: umfgonds@kramare.savba.sk
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