Voltage-dependent potassium currents in cultured human retinal pigment epithelial cells.
Membrane currents in primary cultures of human retinal pigment epithelial cells were studied using the whole-cell configuration of the patch-clamp technique. Two types of voltage-dependent whole-cell currents were observed. First, a time- and voltage-dependent outward current, which was activated by depolarizing the cell to potentials more positive than -30mV, was sensitive to Ba2+ (10mM), 4-aminopyridine (10mM) and TEA+ (30mM). Tail-current analysis indicated that the current was mainly carried by K(+)-ions. Second, hyperpolarization of the cell to potentials more negative than -70mV led to a time- and voltage-dependent inward current which was blocked by Ba2+ (10mM) and 4-aminopyridine (10mM), but not by TEA+ (30mM). In summary, human retinal pigment epithelial cells in primary culture express currents which indicate the presence of a delayed rectifier K(+)-channel and an inward rectifier K(+)-channel.
Strauss
O
O
Dept. Neurobiology, Battelle-Institute, Frankfurt am Main, Germany.
Richard
G
G
Wienrich
M
M
D015761:4-Aminopyridine / Q000494:pharmacology; D000328:Adult; D001464:Barium / Q000494:pharmacology; D046508:Culture Techniques; D006801:Humans; D008564:Membrane Potentials; D008875:Middle Aged; D010857:Pigment Epithelium of Eye / Q000502:physiology*; D011188:Potassium / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects*
D015221:Potassium Channels; D001464:Barium; D015761:4-Aminopyridine; D011188:Potassium