Voltage-dependent Ca2+ channels, not ryanodine receptors, activate Ca2+-dependent BK potassium channels in human retinal pigment epithelial cells.

Abstract

We have shown here for the first time that human RPE cells express BK channels. These channels are activated in RPE cells by increases in [Ca2+]i that are mediated by the opening of voltage gated L-type Ca2+ channels. As Ca2+ entering the RPE cells through these Ca2+ channels are known to be important for growth factor secretion and light-induced transepithelial transport, we speculate that BK channels coupled directly to these Ca2+ channels may provide a good tool for negative feedback control of the L-type Ca2+ channels.