|
|
|
|
|
|
|
||
The Journal of General Physiology, Vol 75, 727-750, Copyright © 1980 by The Rockefeller University Press
ARTICLES |
DC Eaton and MS Brodwick
Ba++ ion blocks K+ conductance at concentrations in the nanomolar range. This blockage is time and voltage dependent. From the time dependence it is possible to determine the forward and reverse rate constants for what appears to be an essentially first-order process of Ba++ interaction. The voltage dependence of the rate constants and the dissociation constants place the site of interaction near the middle of the membrane field. Comparison of the efficacy of Ba++ block at various internal K+ concentrations suggests that Ba++ is probably a simple competitive inhibitor of K+ interaction with the K+ conductance. The character of Ba++ block in high external K+ solutions suggests that Ba++ ion may be "knocked-off" the site by inward movement of external K+. Examination of the effects of other divalent cations suggests that the channel may have a closed state with a divalent cation inside the channel. The relative blockage at different temperatures implies a strong interaction between Ba++ and the K+ conductance.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Facebook 
Reddit 
Technorati 
Twitter What's this?
This article has been cited by other articles:
|
|
 |
|
  M. N. Krishnan, J.-P. Bingham, S. H. Lee, P. Trombley, and E. Moczydlowski Functional Role and Affinity of Inorganic Cations in Stabilizing the Tetrameric Structure of the KcsA K+ Channel J. Gen. Physiol., August 29, 2005; 126(3): 271 - 283. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. del Pilar Gomez and E. Nasi On the Gating Mechanisms of the Light-dependent Conductance in Pecten Hyperpolarizing Photoreceptors: Does Light Remove Inactivation in Voltage-dependent K Channels? J. Gen. Physiol., April 25, 2005; 125(5): 455 - 464. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Gibor, D. Yakubovich, A. Peretz, and B. Attali External Barium Affects the Gating of KCNQ1 Potassium Channels and Produces a Pore Block via Two Discrete Sites J. Gen. Physiol., June 28, 2004; 124(1): 83 - 102. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 U. I. M. Wiehart, G. Klein, P. Steels, S. W. Nicolson, and E. Van Kerkhove K+ transport in Malpighian tubules of Tenebrio molitor L.: is a KATP channel involved? J. Exp. Biol., March 15, 2003; 206(6): 959 - 965. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Weerapura, S. Nattel, M. Courtemanche, D. Doern, N. Ethier, and T. E Hebert State-dependent barium block of wild-type and inactivation-deficient HERG channels in Xenopus oocytes J. Physiol., July 15, 2000; 526(2): 265 - 278. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Jiang and R. MacKinnon The Barium Site in a Potassium Channel by X-Ray Crystallography J. Gen. Physiol., March 1, 2000; 115(3): 269 - 272. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. M. Ogielska and R. W. Aldrich A Mutation in S6 of Shaker Potassium Channels Decreases the K+ Affinity of an Ion Binding Site Revealing Ion-Ion Interactions in the Pore J. Gen. Physiol., August 1, 1998; 112(2): 243 - 257. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Heginbotham, L. Kolmakova-Partensky, and C. Miller Functional Reconstitution of a Prokaryotic K+ Channel J. Gen. Physiol., June 1, 1998; 111(6): 741 - 749. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Holmgren, P. L. Smith, and G. Yellen Trapping of Organic Blockers by Closing of Voltage-dependent K+ Channels: Evidence for a Trap Door Mechanism of Activation Gating J. Gen. Physiol., May 1, 1997; 109(5): 527 - 535. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. H. Gelband and J. R. Hume [Ca2+]i Inhibition of K+ Channels in Canine Renal Artery : Novel Mechanism for Agonist-Induced Membrane Depolarization Circ. Res., July 1, 1995; 77(1): 121 - 130. [Abstract] [Full Text]
|
|
|
|
