TY - JOUR
T1 - Changes in NO bioavailabilty regulate cardiac O2 consumption
T2 - Control by intramitochondrial SOD2 and intracellular myoglobin
AU - Li, Wei
AU - Jue, Thomas
AU - Edwards, John
AU - Wang, Xipping
AU - Hintze, Thomas H.
PY - 2004/1
Y1 - 2004/1
N2 - The aim of this study was to investigate the significance of two intracellular scavengers of nitric oxide (NO): 1) superoxide dismutase (SOD) (SOD2) to scavenge intramitochondrial superoxide anion, and 2) cytosolic myoglobin (Mb) in the regulation of tissue O2 consumption. O 2 consumption was measured in vitro using a Clark-type O2 electrode. SOD heterozygous mice (SODHZ) (n = 13) and SOD wild-type (SODWT) (n = 5) mice were used. Bradykinin (BK, 10-4 mol/l) reduced O 2 consumption by 15% ± 1 in hearts of SODHZ mice, which was significantly different from SODWT (reduced by 24 ± 0.4%). Tiron significantly increased the inhibition of O2 consumption by BK in male mice from 15 ± 1% (n = 13) to 29 ± 1.2% (n = 4) at 10 -4 mol/l concentration (P < 0.05). The effect of carbachol was similar to BK. S-nitroso-N-acetyl penicillamine (SNAP, 10-4 mol/l) reduced O2 consumption by 39 ± 1.3% in hearts of SODHZ mice, which was not significantly different from SODWT. But at 10-7 mol/l, SNAP caused significantly less inhibition of O2 consumption in SODHZ mice. Mb knockout (MbKO; Mb wild-type n = 6) and (MbWT) mice (n = 6) were also used. Kidney cortex was studied as the negative control because it does not contain Mb. BK (10-4 mol/l) reduced O2 consumption by 32 ± 2, 29 ± 1, and 26 ± 1% in the heart, skeletal muscle, and kidney of MbKO mice, which was also not significantly different from MbWT. SNAP (10-4 mol/l) reduced O2 consumption by 39 ± 3, 42 ± 4, and 46 ± 2% in the heart, skeletal muscle, and kidney of MbKO mice, which was also not significantly different from MbWT. N G-nitro-L-arginine methyl ester (P < 0.05) inhibited the reduction in O2 consumption induced by BK in the MbKO mouse heart (15 ± 1%), skeletal muscle (17 ± 1%), and kidney (17 ± 1%) as in the MbWT mice. These results suggest that the role of Mb as an intracellular NO scavenger is small, and the increase in mitochondrial superoxide in SODHZ mice may cause a decrease NO bioavailability and alter the control of myocardial O2 consumption by NO.
AB - The aim of this study was to investigate the significance of two intracellular scavengers of nitric oxide (NO): 1) superoxide dismutase (SOD) (SOD2) to scavenge intramitochondrial superoxide anion, and 2) cytosolic myoglobin (Mb) in the regulation of tissue O2 consumption. O 2 consumption was measured in vitro using a Clark-type O2 electrode. SOD heterozygous mice (SODHZ) (n = 13) and SOD wild-type (SODWT) (n = 5) mice were used. Bradykinin (BK, 10-4 mol/l) reduced O 2 consumption by 15% ± 1 in hearts of SODHZ mice, which was significantly different from SODWT (reduced by 24 ± 0.4%). Tiron significantly increased the inhibition of O2 consumption by BK in male mice from 15 ± 1% (n = 13) to 29 ± 1.2% (n = 4) at 10 -4 mol/l concentration (P < 0.05). The effect of carbachol was similar to BK. S-nitroso-N-acetyl penicillamine (SNAP, 10-4 mol/l) reduced O2 consumption by 39 ± 1.3% in hearts of SODHZ mice, which was not significantly different from SODWT. But at 10-7 mol/l, SNAP caused significantly less inhibition of O2 consumption in SODHZ mice. Mb knockout (MbKO; Mb wild-type n = 6) and (MbWT) mice (n = 6) were also used. Kidney cortex was studied as the negative control because it does not contain Mb. BK (10-4 mol/l) reduced O2 consumption by 32 ± 2, 29 ± 1, and 26 ± 1% in the heart, skeletal muscle, and kidney of MbKO mice, which was also not significantly different from MbWT. SNAP (10-4 mol/l) reduced O2 consumption by 39 ± 3, 42 ± 4, and 46 ± 2% in the heart, skeletal muscle, and kidney of MbKO mice, which was also not significantly different from MbWT. N G-nitro-L-arginine methyl ester (P < 0.05) inhibited the reduction in O2 consumption induced by BK in the MbKO mouse heart (15 ± 1%), skeletal muscle (17 ± 1%), and kidney (17 ± 1%) as in the MbWT mice. These results suggest that the role of Mb as an intracellular NO scavenger is small, and the increase in mitochondrial superoxide in SODHZ mice may cause a decrease NO bioavailability and alter the control of myocardial O2 consumption by NO.
KW - Bradykinin
KW - Carbachol
KW - Myoglobin knockout mouse
KW - S-nitroso-N-acetyl penicillamine
KW - Superoxide dismutase-2 heterozygous mouse
KW - Tiron
UR - http://www.scopus.com/inward/record.url?scp=0347747971&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0347747971&partnerID=8YFLogxK
M3 - Article
C2 - 12919935
AN - SCOPUS:0347747971
VL - 286
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 1 55-1
ER -