Regulation of intracellular pH in cultured bovine retinal pigment epithelial cells

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Item Type:	Article
Title:	Regulation of intracellular pH in cultured bovine retinal pigment epithelial cells
Creators Name:	Keller, S.K., Jentsch, T.J., Janicke, I. and Wiederholt, M.
Abstract:	Regulation of intracellular pH (pHi) in bovine retinal pigment epithelium (RPE) was investigated in cell culture. pHi was measured using the pH-sensitive absorbance of intracellularly trapped 5 (and 6)-carboxy-dimethyl-fluorescein (CDMF). (1) Regulation of pHi after induction of an acid load by removal of NH4Cl could be blocked either totally by removal of extracellular sodium, or subtotally (about 90%) by application of amiloride (1 mmol/l). Additional flux measurements revealed a dose-dependent, amiloride-sensitive 22Na+-uptake into Na+-loaded cells. Both results suggest the presence of a Na+/H+ antiport. (2) When alkalinization of the cells was induced by preincubation with 50 mmol/l acetate in HCO3(-)-Ringer's and subsequent removal of the weak acid, the following regulation was dependent on the presence of extracellular chloride. This process could be blocked with DIDS (1 mmol/l), suggesting the presence of a Cl-/HCO3- exchange mechanism. (3) We found no evidence for a Na+/HCO3(-)-cotransport, which had been postulated to be present in RPE by others. We conclude that two processes are involved in regulation of pHi in RPE: A Na+/H+ antiport responsible for recovery of pHi from acid load, and a DIDS-sensitive Cl-/HCO3- exchange mechanism responsible for recovery of pHi after alkalinization.
Keywords:	Cell Culture, pH Sensitive Dyes, pH Sensitive Absorbance, 5 (and 6)-Carboxy-Dimethylfluorescein, Na+/H+ Antiport, Cl-/HCO 3- Exchange, Animals, Cattle
Source:	Pfluegers Archiv European Journal of Physiology
ISSN:	0031-6768
Publisher:	Springer
Volume:	411
Number:	1
Page Range:	47-52
Date:	January 1988
Official Publication:	https://doi.org/10.1007/BF00581645
PubMed:	View item in PubMed

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