title: Effect of hyperthermia on intracellular pH in human U-87 MG glioblastoma cells.
abstract: The effect of hyperthermia at 43 degrees C on intracellular pH (pHi) in human U-87 MG glioblastoma cells was studied by using the fluorescent probe 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein-pentaacetoxymethyl ester. The presence of Na+/H+ antiporter activity in the cells were demonstrated by the Na(+)-dependent increase in intracellular pH (pHi) after cellular acidification in the absence of HCO3-. Hyperthermia at 43 degrees C caused significant decrease in pHi. The acidification was readily reversible by cooling the cells back down to 37 degrees C. The pHi change was inhibited by the addition of 1 mM amiloride in the incubation medium. Amiloride and hyperthermia exhibited a synergistic effect in suppressing thymidine incorporation into the cells.
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D005456:Fluorescent Dyes; D005909:Glioblastoma / Q000737:chemistry* / Q000473:pathology / Q000628:therapy; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006979:Hyperthermia, Induced; D017923:Sodium-Hydrogen Exchangers / Q000502:physiology*; D013936:Thymidine / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D005456:Fluorescent Dyes; D017923:Sodium-Hydrogen Exchangers; D000584:Amiloride; D013936:Thymidine