Epithelial sodium channels (ENaC) produce extracellular positive DC potentials in the retinal neuroepithelium

Abstract

Positive DC (direct current) potentials were measured in the extracellular space in the retinal neuroepithelium of chick embryos. The positive DC potential was suppressed by amiloride, a blocker for epithelial Na+ channels (ENaC). Amiloride also decreased the resistance of the extracellular space as measured by passing a constant current through a microelectrode. The positive DC potential is necessary for the guidance of retinal ganglion cell axons [1].