Isolated bovine retinal pigment epithelial cells express delayed rectifier type and M-type K+ currents

• DOI: 10.1152/ajpcell.1997.273.3.c790
• Publication Date: 2017-12-24T16:11:29Z
• Authors: M. Takahira; B. A. Hughes
• Keywords: Tetraethylammonium

Outwardly rectifying K+ currents in freshly isolated bovine retinal pigment epithelial (RPE) cells were characterized using the whole cell and perforated-patch configurations of patch-clamp technique. All exhibited a delayed rectifier type current. This current had an activation threshold voltage approximately -40 mV, activated with sigmoidal trajectory, inactivated completely over period several seconds. External tetraethylammonium (TEA) was effective blocker [apparent dissociation constant (Kd) = 5.1 mM], but external Ba2+ relatively ineffective. Approximately 24% also sustained outwardly that became at voltages positive to -80 mV. resembled neuronal M-current. potent this (apparent Kd 1.1 mM), TEA Cs+ These results indicate RPE express both M types. The latter may contribute resting conductances apical basolateral membranes.