Biophysical Journal 67: 2280-2285 (1994)
© 1994 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tu, Q Articles by Fill, M Search for Related Content PubMed PubMed Citation Articles by Tu, Q Articles by Fill, M

Streaming potentials reveal a short ryanodine-sensitive selectivity filter in cardiac Ca2+ release channel.

Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77555-0641.

ABSTRACT

Single cardiac sarcoplasmic reticulum Ca2+ release channels were reconstituted into planar bilayer membranes. Streaming potentials were measured in osmotically asymmetric solutions as a shift in the reversal potential. Potential changes induced by water movement through the bilayer (concentration polarization) and reduced ion activity in the concentrated non-electrolyte solutions were determined using valinomycin. In 400 mM symmetrical CsCH3SO3, the average streaming potential was 2.74 +/- 0.2 mV (n = 5, mean +/- SE; 2 osmol/kg) and independent of the osmoticant used (sucrose or diglycine). Identical streaming potential magnitudes were obtained regardless of which side of the membrane the nonelectrolyte was placed. This suggests that the narrow part of the pore where single file diffusion occurs is relatively short (i.e., accommodates a minimum of 3 H2O molecules). This value is comparable to similar measurements in a variety of surface membrane channels. Ryanodine-modified channels had no measurable streaming potential, an increased Tris+ permeability relative to Cs+, and decreased divalent selectivity (PCs/PTris 5.1 +/- 1.1 to 1.7 +/- 0.3, n = 3; PBa/PCs 8.2 +/- 0.7 to 1.8 +/- 0.5, n = 4). Cation/anion selectivity was essentially unaltered in ryanodine-modified channels. These results suggests that the narrow region of the permeation pathway (i.e., the selectivity filter) is relatively short and widens after ryanodine modification.

This article has been cited by other articles:

				H. Ando, M. Kuno, H. Shimizu, I. Muramatsu, and S. Oiki Coupled K+-Water Flux through the HERG Potassium Channel Measured by an Osmotic Pulse Method J. Gen. Physiol., October 31, 2005; 126(5): 529 - 538. [Abstract] [Full Text] [PDF]

				Y. Wang, L. Xu, D. A. Pasek, D. Gillespie, and G. Meissner Probing the Role of Negatively Charged Amino Acid Residues in Ion Permeation of Skeletal Muscle Ryanodine Receptor Biophys. J., July 1, 2005; 89(1): 256 - 265. [Abstract] [Full Text] [PDF]

				C. G. Perez, J. A. Copello, Y. Li, K. L. Karko, L. Gomez, J. Ramos-Franco, M. Fill, A. L. Escobar, and R. Mejia-Alvarez Ryanodine receptor function in newborn rat heart Am J Physiol Heart Circ Physiol, May 1, 2005; 288(5): H2527 - H2540. [Abstract] [Full Text] [PDF]

				B. Tanna, W. Welch, L. Ruest, J. L. Sutko, and A. J. Williams Voltage-Sensitive Equilibrium between Two States within a Ryanoid-Modified Conductance State of the Ryanodine Receptor Channel Biophys. J., April 1, 2005; 88(4): 2585 - 2596. [Abstract] [Full Text] [PDF]

				W. Welch, S. Rheault, D. J. West, and A. J. Williams A Model of the Putative Pore Region of the Cardiac Ryanodine Receptor Channel Biophys. J., October 1, 2004; 87(4): 2335 - 2351. [Abstract] [Full Text] [PDF]

				J. M. Lee, S.-H. Rho, D. W. Shin, C. Cho, W. J. Park, S. H. Eom, J. Ma, and D. H. Kim Negatively Charged Amino Acids within the Intraluminal Loop of Ryanodine Receptor Are Involved in the Interaction with Triadin J. Biol. Chem., February 20, 2004; 279(8): 6994 - 7000. [Abstract] [Full Text] [PDF]

				L.-Q. Gu, S. Cheley, and H. Bayley Electroosmotic enhancement of the binding of a neutral molecule to a transmembrane pore PNAS, December 23, 2003; 100(26): 15498 - 15503. [Abstract] [Full Text] [PDF]

				R. G. Tsushima, J. E. Kelly, and J. A. Wasserstrom Subconductance Activity Induced by Quinidine and Quinidinium in Purified Cardiac Sarcoplasmic Reticulum Calcium Release Channels J. Pharmacol. Exp. Ther., May 1, 2002; 301(2): 729 - 737. [Abstract] [Full Text] [PDF]

				I. I. Ismailov, V. Gh. Shlyonsky, and D. J. Benos Streaming potential measurements in alpha beta gamma -rat epithelial Na+ channel in planar lipid bilayers PNAS, July 8, 1997; 94(14): 7651 - 7654. [Abstract] [Full Text] [PDF]