Release of repetitive transient potentials and opening of potassium channels by barium in <i>Eremosphaera viridis</i>

Abstract

A concentration‐dependent effect of Ba 2+ on voltage‐independent opening of K + channels in Eremosphaera was examined. Low concentrations of external Ba 2+ (10 −2 mM) cause the release of repetitive transient potentials. Higher concentrations of Ba 2+ , however, inhibit these Ba 2+ ‐induced repetitive and also light‐off triggered transient potentials. Experiments with different Ca 2+ concentrations in the medium and the treatment with La 3+ suggest the interaction of Ba 2+ with Ca 2+ channels and the participation of internal Ca 2+ in the activation of K + channels.