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Voltage change‐induced gating transitions of the rabbit skeletal muscle Ca 2+ release channel
Author(s) -
Zahradníková A.,
Mészáros L. G.
Publication year - 1998
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1998.029bo.x
Subject(s) - gating , biophysics , chemistry , membrane potential , prepulse inhibition , ryanodine receptor , lipid bilayer , coupling (piping) , skeletal muscle , time constant , electrophysiology , membrane , medicine , endocrinology , materials science , biochemistry , endoplasmic reticulum , biology , schizophrenia (object oriented programming) , engineering , computer science , electrical engineering , metallurgy , programming language
1 We used the planar lipid bilayer method to study single ryanodine receptor Ca 2+ release channels (RyRCs) from fast skeletal muscle of the rabbit. We found that changes in membrane voltage directly induced gating transitions of the RyRC: (i) in the steady state, even at activating Ca 2+ concentrations (20 μ m ), at a constant membrane potential the channels resided in a low open probability ( P o ) state (inactivated‐, I‐mode), and (ii) upon abrupt changes of voltage, the apparent inactivation of the RyRCs was relieved, resulting in a rapid and transient increase in P o . 2 The magnitude of the P o increase was a function of both the duration and the amplitude of the applied prepulse, but was independent of the channel activity during the prepulse. 3 The voltage‐induced P o increase probably involved major conformational changes of the channel, as it resulted in substantial alterations in the gating pattern of the channels: the voltage change‐induced increase in P o was accompanied by the rapid appearance of two types of channel activity (high (H) and low (L) open probability modes). 4 The response of the RyRC to voltage changes raises the interesting possibility that the activation of RyRC in situ might involve electrical events, i.e. a possible dipole‐dipole coupling between the release channel and the voltage sensor.