pH regulation in tissue-cultured bovine lens epithelial cells.
The intracellular pH (pHi) of tissue-cultured bovine lens epithelial cells was measured in small groups of 6 to 10 cells using the trapped fluorescent dye 2',7'-bis-(2-,carboxyethyl)-5 (and 6)carboxyfluorescein (BCECF). When perifused at 35 degrees C with artificial aqueous humour solution (AAH) containing 16 mM HCO3- and 5% CO2, pH 7.25, pH(i) was 7.19 +/- 0.02 (SEM, n = 95). On removing HCO3- and CO2 there was an initial transient alkalinization followed by a fall in pH to a steady value of 6.97 +/- 0.03 (SEM, n = 54). Addition of 0.25 mM 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) to AAH containing HCO3- and CO2 led to a rapid and pronounced fall in pH. Exposure to Na(+)-free AAH again led to a marked fall in pH(i), but in this case the addition of DIDS did not produce a further fall. Substitution of the impermeant anion gluconate for Cl- in the presence of HCO3- led to a rise in pHi, while substitution in the absence of HCO3- led to a fall in pHi. The above data indicate a significant role for a sodium-dependent Cl(-)-HCO3- exchange mechanism in the regulation of pHi. Addition of 1 mM amiloride to control AAH in both the presence and absence of HCO3- led to a marked fall in pH(i), indicating that a Na+/H+ exchange mechanism also has a significant role in the regulation of pHi.(ABSTRACT TRUNCATED AT 250 WORDS)
Williams
M R
MR
School of Biological Sciences, University of East Anglia, Norwich, United Kingdom.
Duncan
G
G
Croghan
P C
PC
Riach
R
R
Webb
S F
SF
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000641:Ammonia / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D001692:Biological Transport / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology; D002417:Cattle; D027963:Chloride-Bicarbonate Antiporters; D004847:Epithelial Cells; D004848:Epithelium / Q000502:physiology; D005434:Flow Cytometry; D005452:Fluoresceins; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000493:pharmacokinetics; D007908:Lens, Crystalline / Q000166:cytology* / Q000502:physiology*; D009924:Organ Culture Techniques; D011343:Procaine / Q000494:pharmacology; D012964:Sodium / Q000502:physiology; D017923:Sodium-Hydrogen Exchangers
D001639:Bicarbonates; D002352:Carrier Proteins; D027963:Chloride-Bicarbonate Antiporters; D005452:Fluoresceins; D007773:Lactates; D017923:Sodium-Hydrogen Exchangers; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D011343:Procaine; D000641:Ammonia; D000584:Amiloride; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D012964:Sodium; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid