Abstract
We have previously shown that a reduction of intracellular ionic strength is involved in the activation of volume-regulated anion channels (VRAC). Here we show in a single-channel study that VRAC can be activated in a cell-attached patch when the cell interior is dialyzed with a solution of decreased ionic strength. For this purpose, bovine pulmonary endothelial (CPAE) cells) were permeabilized with α-staphylotoxin (αST) which has a molecular weight cut-off size of 2 kDa. If the ionic strength in the bath solution is reduced from 160 mM to 95 mM, single-channel activity is initiated in cell-attached patches sealed before permeabilization. Conductance is outwardly rectifying with approximately 17 pS at negative and 57 pS at positive potentials. Single-channel currents reverse near the calculated equilibrium potential for Cl–. The averaged current shows inactivation at positive potentials. The current is blocked by 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB). An increase in ionic strength reversibly inhibits current activation. It is concluded that a decrease in ionic strength activates single-channel currents through VRAC rather than shifting the set point of a hypothetical volume sensor.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received after revision and accepted: 1 October 1999
Electronic Publication
Rights and permissions
About this article
Cite this article
Sabirov, R., Prenen, J., Tomita, T. et al. Reduction of ionic strength activates single volume-regulated anion channels (VRAC) in endothelial cells. Pflügers Arch – Eur J Physiol 439, 315–320 (2000). https://doi.org/10.1007/s004249900186
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s004249900186