OBJECTIVE: The aims of the present study were to elucidate the interaction of reactive oxygen species (ROS) and Ca(2+) response in central nervous system (CNS) pericytes. METHODS: The intracellular Ca(2+) concentration was measured using fluorescent Ca(2+) indicator, fura-2, in cultured CNS pericytes. RESULTS: Hydrogen peroxide evoked a dose-dependent increase in cytosolic Ca(2+), which was completely inhibited by catalase. Removal of external Ca(2+) or addition of nicardipine (1 microM) during application of hydrogen peroxide did not affect Ca(2+) response. Incubation of the cells in Ca(2+) free solution did not abolish but slightly reduced Ca(2+) response by hydrogen peroxide. Ca(2+) response to hydrogen peroxide was not altered by the depletion of intracellular Ca(2+) by thapsigargin (1 microM). Pretreatment of the cells with tyrosine kinase inhibitor genistein (100 microM) or tyrphostin A47 (30 microM) significantly reduced Ca(2+) increase by hydrogen peroxide. CONCLUSIONS: These results indicate that hydrogen peroxide evokes Ca(2+) increase predominantly by release from intracellular Ca(2+) store, which may be regulated by tyrosine kinases.
OBJECTIVE: The aims of the present study were to elucidate the interaction of reactive oxygen species (ROS) and Ca(2+) response in central nervous system (CNS) pericytes. METHODS: The intracellular Ca(2+) concentration was measured using fluorescent Ca(2+) indicator, fura-2, in cultured CNS pericytes. RESULTS:Hydrogen peroxide evoked a dose-dependent increase in cytosolic Ca(2+), which was completely inhibited by catalase. Removal of external Ca(2+) or addition of nicardipine (1 microM) during application of hydrogen peroxide did not affect Ca(2+) response. Incubation of the cells in Ca(2+) free solution did not abolish but slightly reduced Ca(2+) response by hydrogen peroxide. Ca(2+) response to hydrogen peroxide was not altered by the depletion of intracellular Ca(2+) by thapsigargin (1 microM). Pretreatment of the cells with tyrosine kinase inhibitor genistein (100 microM) or tyrphostin A47 (30 microM) significantly reduced Ca(2+) increase by hydrogen peroxide. CONCLUSIONS: These results indicate that hydrogen peroxide evokes Ca(2+) increase predominantly by release from intracellular Ca(2+) store, which may be regulated by tyrosine kinases.