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Anion-Sensitive Regions Of L-Type Cav1.2 Calcium Channels Expressed In Hek293 Cells., Norbert Babai, Nataly Kanevsky, Nathan Dascal, George J. Rozanski, Dhirendra P. Singh, Nigar Fatma, Wallace B. Thoreson

Journal Articles: Ophthalmology

L-type calcium currents (I(Ca)) are influenced by changes in extracellular chloride, but sites of anion effects have not been identified. Our experiments showed that CaV1.2 currents expressed in HEK293 cells are strongly inhibited by replacing extracellular chloride with gluconate or perchlorate. Variance-mean analysis of I(Ca) and cell-attached patch single channel recordings indicate that gluconate-induced inhibition is due to intracellular anion effects on Ca(2+) channel open probability, not conductance. Inhibition of CaV1.2 currents produced by replacing chloride with gluconate was reduced from approximately 75%-80% to approximately 50% by omitting beta subunits but unaffected by omitting alpha(2)delta subunits. Similarly, gluconate inhibition was …