ISSN:
1432-2013
Schlagwort(e):
Cell culture
;
pH sensitive dyes
;
pH sensitive absorbance
;
5 (and 6)-carboxy-dimethylfluorescein
;
Na+/H+ antiport
;
Cl−/HCO 3 − exchange
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
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-sensitive22Na+-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 HCO 3 − -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−/HCO 3 − exchange mechanism. (3) We found no evidence for a Na+/HCO 3 − -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−/HCO 3 − exchange mechanism responsible for recovery of pHi after alkalinization.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00581645
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