IDENTIFICATION OF SODIUM-CHANNEL SUBTYPES INDUCED IN CULTURED RETINAL-PIGMENT EPITHELIUM-CELLS

Recent electrophysiological experiments have shown that retinal pigmen t epithelium (RPE) cells begin to produce neuronal-type voltage-depend ent sodium currents when placed in dissociated cell culture. In this s tudy, the sodium channel types induced in cultured rat RPE cells were identified. Sodium channel mRNAs encoding two distinct alpha subunits were detected in the cultured RPE cells, brain type II/IIA, and a nove l rat mRNA which we have termed RET1. These two sodium channel types m ay correspond to the TTX-sensitive and TTX-insensitive components of s odium current reported previously in cultured rat RPE cells.