| Autor: |
Sabirov, R. Z., Prenen, J., Tomita, T., Droogmans, G., Nilius, B. |
| Předmět: |
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| Zdroj: |
Pflügers Archiv: European Journal of Physiology; Jan2000, Vol. 439 Issue 3, p315-320, 6p |
| Abstrakt: |
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. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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