Bioelectrical properties of Chara gymnophylla plasmamembrane during interaction with cobalt, $(Co^{2+})$

Abstract

The regularities of membrane potential (Em) and resistance (Rm) changes of internodal Chara gymnophylla cells' using Co2+ (10-7-10-3M) were investigated by a microelectrode method. The aim of this work was to ascertain the mechanisms that the initial action of Co2+ had on the level of the cell membrane. The primary effect of Co2+ was found to be plasma-lemma hyper polarization, determined by a cation concentration and initial level of Em. The highest value of plasmalemma hyper polarization (45-70mV) was observed on cells with an initial Em= -160mV under the influence of Co2+ in the concentration of 10-3M in the medium. The hyper polarization of plasmalemma was accompanied by an Rm increase up to 50%. The reactions of Em and Rm with the addition of Co2+ to the medium turned out to be irreversible. The restoration of Em and Rm to the initial levels was obtained by the combined addition of Co2+ with 10mM of K+. It seems possible that the Co2+ effects are connected with cation action on passive permeability by the means of weak interaction of the cation with inputs of K+ channels of plasmalemma.