Transmembrane calcium influx induced by ac electric fields

摘要: Exogenous electric fields induce cellular responses including redistribution of integral membrane proteins, reorganization microfilament structures, and changes in intracellular calcium ion concentration ([Ca2+]i). Although increases [Ca2+]i caused by application direct current have been documented, quantitative measurements the effects alternating (ac) on are lacking Ca2+ pathways that mediate such remain to be identified. Using epifluorescence microscopy, we examined a model cell type response ac fields. Application 1 or 10 Hz field human hepatoma (Hep3B) cells induces fourfold increase (from 50 nM 200 nM) within 30 min continuous exposure. Depletion extracellular medium prevents field-induced [Ca2+]i, suggesting influx across plasma is responsible for increase. Incubation with phospholipase C inhibitor U73122 does not inhibit receptor-regulated release important this effect. Treatment either stretch-activated cation channel GdCl3 nonspecific blocker CoCl2 partially inhibits induced fields, concomitant treatment both completely Since neither Gd3+ nor Co2+ efficiently transported membrane, these data suggest depends entirely from medium.