Korean J Physiol Pharmacol.
1998 Oct;2(5):549-553.
Dual action of d-tubocurarine on large-conductance Ca2+-activated K+ channels from rat brain reconstituted into planar lipid bilayer
- Affiliations
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- 1Department of Physiology, Chung-Ang University College of Medicine, Seoul 156-756, Korea.
- 2Department of Physiology and Biophysics, Inha University College of Medicine, Inchon 402-751, Korea.
Abstract
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Using the planar lipid bilayer method, we investigated the effect of
d-tubocurarine (dTC) on the extracellular side of large-conductance
Ca2+-activated K+ channel from rat brain. When the initial open
probability (Po) of the channel was relatively high, dTC decreased
channel activity in a concentration dependent manner. In contrast, when
the initial Po was lower, sub-micro molar dTC increased channel
activity by destabilizing the closed states of the channel. Further
addition of dTC up to micro molar range decreased channel activity.
This dual effect of dTC implicates that there exist at least two
different binding sites for dTC.