[Regulation of intracellular pH by Na+/H+ exchange in human lymphocytes].
Spectrofluorimetry and the pH-sensitive fluorescent dye 2',7'-bis(carboxyethyl)-5(6)carboxyfluorescein (BCECF) was used to measure the intracellular pH (pHi) of suspended human lymphocytes. A linear relationship exists between pHi and the fluorescent spinal-ratio (I490nm/I435nm, emission 526 nm) between pH 6.5 and pH 7.8. At the end of each experiment the ratio was calibrated using the high [K+] nigericin technique. All solutions were HEPES buffered. The pHi in resting cells was 7.27 +/- 0.02 (n = 37) at 25 degrees C. Na+ free solution caused a pHi decrease to 6.81 +/- 0.08. The ammonium prepulse technique (25 mM NH4Cl) dropped the pHi to pH 6.80. A rapid recovery of the pHi after this acidification was observed in NaCl Ringer solution. Na+ free solution completely blocked the recovery. 1 mM amiloride led to a partial block of recovery. pHi was restored to the basal value after readdition of Na+. We conclude that in HEPES buffered solutions human lymphocytes recover pHi via a mechanism dependent on extracellular Na+ and largely accomplished by an amiloride inhibitory Na+/H+ exchanger.
Weinlich
M
M
I. Chirurgische Universitätsklinik, Wien.
Wenzl
E
E
Starlinger
M
M
Schiessel
R
R
D000136:Acid-Base Equilibrium / Q000187:drug effects; D000584:Amiloride / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006801:Humans; D008214:Lymphocytes / Q000502:physiology*; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000502:physiology; D013050:Spectrometry, Fluorescence
D005452:Fluoresceins; D005456:Fluorescent Dyes; D015222:Sodium Channels; D000584:Amiloride; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D012964:Sodium
Die Regulation des intrazellulären pH durch einen Na+/H+-Austauscher in humanen Lymphozyten.