Novel inward rectifier blocked by Cd2+ in crayfish muscle

Abstract

The characteristics of a voltage- and time-dependent inward rectifying current were examined with voltage clamp techniques in crayfish muscle. The inward current, carried by K+, was activated by hyperpolarization. Although this inward current increased with the extracellular K+ concentration [( K+]o), the voltage-dependence of the underlying conductance was independent of [K+]o. The current was unaffected by Cs+ and Ba2+, but was blocked by low concentrations of Cd2+. Therefore, this inward rectifier is different than previously described ones.