Extracellular chloride modulates the desensitization kinetics of acid-sensing ion channel 1a (ASIC1a).

ABSTRACT: Acid-sensing ion channels (ASICs) are sodium channels gated by extracellular protons. The recent crystallization of ASIC1a identified potential binding sites for Cl(-) in the extracellular domain that are highly conserved between ASIC isoforms. However, the significance of Cl(-) binding is unknown. We investigated the effect of Cl(-) substitution on heterologously expressed ASIC1a current and H(+)-gated currents from hippocampal neurons recorded by whole-cell patch clamp. Replacement of extracellular Cl(-) with the impermeable and inert anion methanesulfonate (MeSO(3)(-)) caused ASIC1a currents to desensitize at a faster rate and attenuated tachyphylaxis. However, peak current amplitude, pH sensitivity, and selectivity were unchanged. Other anions, including Br(-), I(-), and thiocyanate, a

SUBMITTER: Kusama N 

PROVIDER: S-EPMC2878506 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature