Abstract
It is controversial whether the ClC-3 protein, which is one of the voltage-dependent chloride channel ClC family members, is a candidate of the volume-sensitive outwardly rectifying (VSOR) Cl− channel per se or its regulator. We here, for the first time, examined single-channel properties of the VSOR Cl− channel in ventricular myocytes isolated from ClC-3–deficient mice. The single-channel current induced by cell swelling exhibited Cl− selectivity, mild outward rectification and an intermediate unitary conductance (around 38 pS). A Cl− channel blocker, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) reversibly inhibited the outward current. These single-channel properties were identical with those in ClC-3 expressing wild-type ventricular myocytes. These results indicate that the single-channel activity of VSOR Cl− channel is independent of the expression of ClC-3 proteins in mouse ventricular myocytes.
