TY - JOUR
T1 - Carbon monoxide inhibition of regulatory pathways in myocardium
AU - Glabe, Alan
AU - Chung, Youngran
AU - Dejun, X. U.
AU - Jue, Thomas
PY - 1998
Y1 - 1998
N2 - The 1H nuclear magnetic resonance (NMR) myoglobin (Mb) Val E11 signal provides a unique opportunity to assess the functional role of Mb in the cell. On CO infusion in perfused myocardium, the MbO2 signal at -2.76 parts per million (ppm) gradually disappears, whereas the corresponding MbCO signal emerges at -2.26 ppm, reflecting the state of Mb inhibition. Up to 76.8% MbCO saturation, myocardial O2 consumption (MV̇O2) remains constant, whereas the rate-pressure product (RPP) has already dropped to 92% of the control level. At 87.6% MbCO saturation, the lactate formation rate has increased by a factor of two, and ṀO2 begins to decline. However, the ratio CO/O2 is still 1/10, well below the inhibition threshold for cytochrome oxidase activity. The ṀO2 decline in the face of an adequate O2 supply and an unperturbed high-energy phosphate level implies that Mb may play a role in directly regulating respiration, mediated potentially by a shift in NADH/NAD. Although nitrite inhibits Mb, nitrite also directly affects the myocardial function.
AB - The 1H nuclear magnetic resonance (NMR) myoglobin (Mb) Val E11 signal provides a unique opportunity to assess the functional role of Mb in the cell. On CO infusion in perfused myocardium, the MbO2 signal at -2.76 parts per million (ppm) gradually disappears, whereas the corresponding MbCO signal emerges at -2.26 ppm, reflecting the state of Mb inhibition. Up to 76.8% MbCO saturation, myocardial O2 consumption (MV̇O2) remains constant, whereas the rate-pressure product (RPP) has already dropped to 92% of the control level. At 87.6% MbCO saturation, the lactate formation rate has increased by a factor of two, and ṀO2 begins to decline. However, the ratio CO/O2 is still 1/10, well below the inhibition threshold for cytochrome oxidase activity. The ṀO2 decline in the face of an adequate O2 supply and an unperturbed high-energy phosphate level implies that Mb may play a role in directly regulating respiration, mediated potentially by a shift in NADH/NAD. Although nitrite inhibits Mb, nitrite also directly affects the myocardial function.
KW - Myoglobin
KW - Nuclear magnetic resonance
KW - Oxidative phosphorylation
KW - Respiration
UR - http://www.scopus.com/inward/record.url?scp=0031859923&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031859923&partnerID=8YFLogxK
M3 - Article
C2 - 9841541
AN - SCOPUS:0031859923
VL - 274
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 6 43-6
ER -