Interactions of pH and K+ conductance in cultured bovine retinal pigment epithelial cells

Item Type:	Article
Title:	Interactions of pH and K+ conductance in cultured bovine retinal pigment epithelial cells
Creators Name:	Keller, S.K. and Jentsch, T.J. and Koch, M. and Wiederholt, M.
Abstract:	Passive ion transport properties were studied in confluent monolayers of cultured bovine retinal pigment epithelial cells using intracellular microelectrode technique. The mean stable intracellular (designated by subscript i) potential was -59.1 +/- 0.8 (SE) mV. Extracellular (designated by subscript o) acidification induced a depolarization, whereas alkalinization induced a hyperpolarization. These effects were observed both in bicarbonate-free as well as in HCO3- Ringer (pHo changed by varying [HCO3-]o at constant pCO2). Acidification of pHi (changed by addition and removal of butyrate, CO2 or NH3) also caused a depolarization. Complete removal of HCO3-/CO2 at constant pHo caused a hyperpolarization. K+ transference, checked by applying high K+o, increased with K+o. It decreased with both extra and intracellular acidification and increased with alkalinization. In the presence of Ba2+, voltage reactions to changes in either pHo or pHi were greatly reduced. Depolarization by 40 mM K+ caused a similar reduction. It is suggested that K+ conductance of bovine retinal pigment epithelial cells is reduced by either intra- or extracellular acidification at normal [K+]o. Depolarization by high K+ induces an increase in K+ transference and reduces pH sensitivity.
Keywords:	Action Potentials, Ammonium Chloride, Barium, Bicarbonates, Cultured Cells, Electric Conductivity, Hydrogen-Ion Concentration, Mathematics, Pigment Epithelium of Eye, Potassium, Animals, Cattle
Source:	American Journal of Physiology
ISSN:	0002-9513
Publisher:	American Physiological Society
Volume:	250
Number:	1 Pt 1
Page Range:	C124-C137
Date:	January 1986
Official Publication:	http://ajpcell.physiology.org/cgi/content/abstract/250/1/C124
PubMed:	View item in PubMed

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