Role of Cu,Zn-SOD in the synthesis of endogenous vasodilator hydrogen peroxide during reactive hyperemia in mouse mesenteric microcirculation in vivo

Toyotaka Yada, Hiroaki Shimokawa, Keiko Morikawa, Aya Takaki, Yoshiro Shinozaki, Hidezo Mori, Masami Goto, Yasuo Ogasawara, Fumihiko Kajiya

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

We have recently demonstrated that endothelium-derived hydrogen peroxide (H2O2) is an endothelium-derived hyperpolarizing factor and that endothelial Cu/Zn-superoxide dismutase (SOD) plays an important role in the synthesis of endogenous H2O2 in both animals and humans. We examined whether SOD plays a role in the synthesis of endogenous H2O 2 during in vivo reactive hyperemia (RH), an important regulatory mechanism. Mesenteric arterioles from wild-type and Cu,Zn-SOD-/- mice were continuously observed by a pencil-type charge-coupled device (CCD) intravital microscope during RH (reperfusion after 20 and 60 s of mesenteric artery occlusion) in the cyclooxygenase blockade under the following four conditions: control, catalase alone, NG-monomethyl-L-arginine (L-NMMA) alone, and L-NMMA + catalase. Vasodilatation during RH was significantly decreased by catalase or L-NMMA alone and was almost completely inhibited by L-NMMA + catalase in wild-type mice, whereas it was inhibited by L-NMMA and L-NMMA + catalase in the Cu,Zn-SOD-/- mice. RH-induced increase in blood flow after L-NMMA was significantly increased in the wild-type mice, whereas it was significantly reduced in the Cu,Zn-SOD-/- mice. In mesenteric arterioles of the Cu,Zn-SOD-/- mice, Tempol, an SOD mimetic, significantly increased the ACh-induced vasodilatation, and the enhancing effect of Tempol was decreased by catalase. Vascular H 2O2 production by fluorescent microscopy in mesenteric arterioles after RH was significantly increased in response to ACh in wild-type mice but markedly impaired in Cu,Zn-SOD-/- mice. Endothelial Cu,Zn-SOD plays an important role in the synthesis of endogenous H 2O2 that contributes to RH in mouse mesenteric smaller arterioles.

Original languageEnglish
Pages (from-to)H441-H448
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume294
Issue number1
DOIs
Publication statusPublished - 2008 Jan

Keywords

  • Arteriole
  • Endothelium-derived hyperpolarizing factor
  • Nitric oxide
  • Vasodilatation

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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