Gap junctional conductance: comparison of sensitivities to H and Ca ions.

Abstract
One cytoplasmic aspect of the junctional membrane between coupled pairs of Fundulus heteroclitus blastomeres was perfused with solutions of known H+ and Ca2+ concentrations. Conductance of junctional membrane was decreased by either ion. The sensitivity to H+ was .apprx. 10,000 times greater than that to Ca2+. Apparently junctional conductance can be modulated by changes in H+ concentration near physiological pH but unphysiologically high concentrations of Ca2+, such as would be reached only on cell death, are required for comparable changes in junctional conductance.