Hydrogen peroxide-induced Ca2+ responses in CNS pericytes.
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.
Kamouchi
Masahiro
M
Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Fukuoka, Japan. kamouchi@intmed2.med.kyushu-u.ac.jp
Kitazono
Takanari
T
Ago
Tetsuro
T
Wakisaka
Masanori
M
Kuroda
Junya
J
Nakamura
Kuniyuki
K
Hagiwara
Noriko
N
Ooboshi
Hiroaki
H
Ibayashi
Setsuro
S
Iida
Mitsuo
M
D000818:Animals; D001812:Blood-Brain Barrier / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects* / Q000502:physiology; D002374:Catalase / Q000494:pharmacology; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008297:Male; D008833:Microcirculation / Q000502:physiology; D016877:Oxidants / Q000494:pharmacology*; D020286:Pericytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D019284:Thapsigargin / Q000494:pharmacology
D004791:Enzyme Inhibitors; D016877:Oxidants; D017382:Reactive Oxygen Species; D019284:Thapsigargin; D006861:Hydrogen Peroxide; D019833:Genistein; D002374:Catalase; D002118:Calcium