Premium
Real time measurement of hydrogen peroxide (H 2 O 2 )and nitric oxide (NO) release in femoral vein ischemia and reperfusion (I/R): The effects of tetrahydrobiopterin (BH 4 )/dihydrobiopterin (BH 2 ) and the effects of Protein Kinase C (PKC) epsilon activation (ε+)/inhibition (ε−)
Author(s) -
Zambrano Christopher John,
Krass Samuel,
Chen Qian,
Young Lindon Howard
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.730.1
Subject(s) - enos , chemistry , nitric oxide , hydrogen peroxide , femoral artery , ischemia , femoral vein , reperfusion injury , tetrahydrobiopterin , protein kinase c , superoxide , medicine , endocrinology , nitric oxide synthase , anesthesia , biochemistry , enzyme
Endothelial nitric oxide synthase (eNOS) is a possible source of oxidative stress (i.e., superoxide (SO) and H 2 O 2 ) during reperfusion in which BH 4 is oxidized to BH 2 . Moreover, PKC ε positively regulates NO and SO release from eNOS. The effects of BH 4 /BH 2 or PKC ε +/ε− on NO and H 2 O 2 release have not been directly estimated by real‐time measurement in blood vessels during I/R in vivo . NO and H 2 O 2 were directly measured by inserting either NO or H 2 O 2 microsensors (100 μm diameter) into both femoral veins in the anesthetized rat. One femoral vein was subjected to I/R, which was induced by clamping the femoral artery and vein for 20 min ischemia followed by removing the clamp for 45 min reperfusion. The other non‐ischemic femoral vein served as a sham control in the same animal. H 2 O 2 release increased throughout the first 20 min of reperfusion compared to the sham control. PKC ε− (0.4 mg/kg) or BH 4 (6.5 mg/kg) significantly reduced H 2 O 2 release while PKC ε+ (0.9mg/kg) or BH 2 (2mg/kg) showed a trend to increase H 2 O 2 release throughout reperfusion. BH 4 significantly increased NO release while BH 2 showed a trend to decrease NO release. The preliminary data thus far support our hypothesis that BH 4 or PKC ε− decrease H 2 O 2 release during reperfusion whereas the opposite effect is observed with BH2 or PKC ε+. This study was supported by NHLBI Grant 1R15HL‐76235‐01 and Center For Chronic Disorders of Aging at PCOM