[HTML][HTML] Regulation of intracellular pH in cultured hippocampal neurons by an amiloride-insensitive Na+/H+ exchanger.
KM Raley-Susman, EJ Cragoe Jr, RM Sapolsky… - Journal of Biological …, 1991 - Elsevier
KM Raley-Susman, EJ Cragoe Jr, RM Sapolsky, RR Kopito
Journal of Biological Chemistry, 1991•ElsevierRegulation of intracellular pH (pHi) in single cultured rat hippocampal neurons was
investigated using the fluorescent pHi indicator dye bis-carboxyethylcarboxyfluorescein.
Resting pHi was dependent on the presence of bicarbonate and external Na+ but was not
altered significantly by removal of Cl-or treatment with the anion exchange inhibitor
diisothiocyanatostilbene-2, 2'-disulfonate. Recovery of pHi from acute acid loading was due,
in large part, to a pharmacologically distinct variant of the Na+/H+ antiporter. In nominally …
investigated using the fluorescent pHi indicator dye bis-carboxyethylcarboxyfluorescein.
Resting pHi was dependent on the presence of bicarbonate and external Na+ but was not
altered significantly by removal of Cl-or treatment with the anion exchange inhibitor
diisothiocyanatostilbene-2, 2'-disulfonate. Recovery of pHi from acute acid loading was due,
in large part, to a pharmacologically distinct variant of the Na+/H+ antiporter. In nominally …
Regulation of intracellular pH (pHi) in single cultured rat hippocampal neurons was investigated using the fluorescent pHi indicator dye bis-carboxyethylcarboxyfluorescein. Resting pHi was dependent on the presence of bicarbonate and external Na+ but was not altered significantly by removal of Cl- or treatment with the anion exchange inhibitor diisothiocyanatostilbene-2,2'-disulfonate. Recovery of pHi from acute acid loading was due, in large part, to a pharmacologically distinct variant of the Na+/H+ antiporter. In nominally HCO3(-)-free solutions, this recovery exhibited a saturable dose dependence on extracellular Na+ (Km = 23-26 mM) or Li+. The antiporter was activated by decreasing pHi and was unaffected by collapse of the membrane potential with valinomycin. Like the Na+/H+ antiporter described in other cell systems, the hippocampal activity was inhibited by harmaline, but in sharp contrast, neither amiloride nor its more potent 5-amino-substituted analogues were able to prevent the recovery from an acid load. These data indicate that Na(+)-dependent mechanisms dominate pHi regulation in hippocampal neurons and suggest a role for a novel variant of the Na+/H+ antiporter.
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