Single sodium channels from human ventricular muscle in planar lipid bilayers

2001 ◽  
Vol 96 (6) ◽  
pp. 645-651 ◽  
Author(s):  
Hans C. Wartenberg ◽  
Jan P. Wartenberg ◽  
Bernd W. Urban
Keyword(s):  
Lipid Bilayers ◽  
Sodium Channels ◽  
Planar Lipid Bilayers ◽  
Ventricular Muscle ◽  
Single Sodium Channels

Neuraminidase treatment modifies the function of electroplax sodium channels in planar lipid bilayers

Neuron ◽  
1990 ◽  
Vol 5 (5) ◽  
pp. 675-684 ◽  
Author(s):  
Esperanza Recio-Pinto ◽  
William B. Thornhill ◽  
Daniel S. Duch ◽  
Simon R. Levinson ◽  
Bernd W. Urban
Keyword(s):  
Lipid Bilayers ◽  
Sodium Channels ◽  
Planar Lipid Bilayers ◽  
Neuraminidase Treatment

scholarly journals Batrachotoxin-modified sodium channels in planar lipid bilayers. Characterization of saxitoxin- and tetrodotoxin-induced channel closures.

1987 ◽  
Vol 89 (6) ◽  
pp. 873-903 ◽  
Author(s):  
W N Green ◽  
L B Weiss ◽  
O S Andersen
Keyword(s):  
Binding Site ◽  
Lipid Bilayers ◽  
Sodium Channels ◽  
Conformational Changes ◽  
Single Channel ◽  
Planar Lipid Bilayers ◽  
Net Charge ◽  
Toxin Binding ◽  
Wide Range ◽  
Voltage Dependent

The guanidinium toxin-induced inhibition of the current through voltage-dependent sodium channels was examined for batrachotoxin-modified channels incorporated into planar lipid bilayers that carry no net charge. To ascertain whether a net negative charge exists in the vicinity of the toxin-binding site, we studied the channel closures induced by tetrodotoxin (TTX) and saxitoxin (STX) over a wide range of [Na+]. These toxins carry charges of +1 and +2, respectively. The frequency and duration of the toxin-induced closures are voltage dependent. The voltage dependence was similar for STX and TTX, independent of [Na+], which indicates that the binding site is located superficially at the extracellular surface of the sodium channel. The toxin dissociation constant, KD, and the rate constant for the toxin-induced closures, kc, varied as a function of [Na+]. The Na+ dependence was larger for STX than for TTX. Similarly, the addition of tetraethylammonium (TEA+) or Zn++ increased KD and decreased kc more for STX than for TTX. These differential effects are interpreted to arise from changes in the electrostatic potential near the toxin-binding site. The charges giving rise to this potential must reside on the channel since the bilayers had no net charge. The Na+ dependence of the ratios KDSTX/KDTTX and kcSTX/kcTTX was used to estimate an apparent charge density near the toxin-binding site of about -0.33 e X nm-2. Zn++ causes a voltage-dependent block of the single-channel current, as if Zn++ bound at a site within the permeation path, thereby blocking Na+ movement. There was no measurable interaction between Zn++ at its blocking site and STX or TTX at their binding site, which suggests that the toxin-binding site is separate from the channel entrance. The separation between the toxin-binding site and the Zn++ blocking site was estimated to be at least 1.5 nm. A model for toxin-induced channel closures is proposed, based on conformational changes in the channel subsequent to toxin binding.

Block of Sodium Channels in Planar Lipid Bilayers by Guanidinium Toxins and Calcium.

1986 ◽  
Vol 479 (1 Tetrodotoxin,) ◽  
pp. 257-268 ◽  
Author(s):  
BRUCE K. KRUEGER ◽  
JENNINGS F. WORLEY ◽  
ROBERT J. FRENCH
Keyword(s):  
Lipid Bilayers ◽  
Sodium Channels ◽  
Planar Lipid Bilayers

Functional Reconstitution of Purified Sodium Channels from Brain in Planar Lipid Bilayers

1986 ◽  
Vol 479 (1 Tetrodotoxin,) ◽  
pp. 293-305 ◽  
Author(s):  
ROBERT P. HARTSHORNE ◽  
BERNARD U. KELLER ◽  
JANE A. TALVENHEIMO ◽  
WILLIAM A. CATTERALL ◽  
MAURICIO MONTAL
Keyword(s):  
Lipid Bilayers ◽  
Sodium Channels ◽  
Planar Lipid Bilayers

scholarly journals Sodium channels in planar lipid bilayers. Channel gating kinetics of purified sodium channels modified by batrachotoxin.

1986 ◽  
Vol 88 (1) ◽  
pp. 1-23 ◽  
Author(s):  
B U Keller ◽  
R P Hartshorne ◽  
J A Talvenheimo ◽  
W A Catterall ◽  
M Montal
Keyword(s):  
Lipid Bilayers ◽  
Sodium Channels ◽  
Single Channel ◽  
Channel Gating ◽  
Neuroblastoma Cells ◽  
Planar Lipid Bilayers ◽  
Transition Rates ◽  
Biophysical Journal ◽  
Single Channel Currents ◽  
Kinetics Of

Single channel currents of sodium channels purified from rat brain and reconstituted into planar lipid bilayers were recorded. The kinetics of channel gating were investigated in the presence of batrachotoxin to eliminate inactivation and an analysis was conducted on membranes with a single active channel at any given time. Channel opening is favored by depolarization and is strongly voltage dependent. Probability density analysis of dwell times in the closed and open states of the channel indicates the occurrence of one open state and several distinct closed states in the voltage (V) range-120 mV less than or equal to V less than or equal to +120 mV. For V less than or equal to 0, the transition rates between stages are exponentially dependent on the applied voltage, as described in mouse neuroblastoma cells (Huang, L. M., N. Moran, and G. Ehrenstein. 1984. Biophysical Journal. 45:313-322). In contrast, for V greater than or equal to 0, the transition rates are virtually voltage independent. Autocorrelation analysis (Labarca, P., J. Rice, D. Fredkin, and M. Montal. 1985. Biophysical Journal. 47:469-478) shows that there is no correlation in the durations of successive open or closing events. Several kinetic schemes that are consistent with the experimental data are considered. This approach may provide information about the mechanism underlying the voltage dependence of channel activation.

Sign in / Sign up

Export Citation Format

Share Document