Direct evidence for calcium conductance of hyperpolarization-activated cyclic nucleotide-gated channels and human native If at physiological calcium concentrations

Abstract

We directly show Ca(2+) permeability of native rat and, more importantly, human I(f) at physiological extracellular Ca(2+) concentrations at the physiological resting membrane potential. This might have particular implications in diseased states with increased I(f) density and HCN expression.