TY - JOUR
T1 - Brain high-energy phosphates and creatine kinase synthesis rate under graded isoflurane anesthesia
T2 - An in vivo 31P magnetization transfer study at 11.7 Tesla
AU - Bresnen, Andrew
AU - Duong, Timothy Q.
N1 - Publisher Copyright:
© 2014 Wiley Periodicals, Inc.
PY - 2015/2/1
Y1 - 2015/2/1
N2 - Purpose: The creatine kinase rate of metabolic adenosine triphosphate (ATP) synthesis is an important metabolic parameter but is challenging to measure in vivo due to limited signal-to-noise ratio and long measurement time. Theory and Methods: This study reports the implementation of an accelerated 31P Four Angle Saturation Transfer (FAST) method to measure the forward creatine kinase (CK) rate of ATP synthesis. Along with a high-field scanner (11.7 Tesla) and a small sensitive surface coil, the forward CK rate in the rat brain was measured in ∼5 min. Results: Under 1.2% isoflurane, the forward CK rate constant and metabolic flux were, respectively, kf,CK = 0.26 ± 0.02 s-1 and Ff,CK = 70.8 ± 4.6 μmol/g/min. As a demonstration of utility and sensitivity, measurements were made under graded isoflurane. Under 2.0% isoflurane, kf,CK = 0.16 ± 0.02 s-1 and Ff,CK = 41.0 ± 4.2 μmol/g/min, corresponding to a 38% and 42% reduction, respectively, relative to 1.2% isoflurane. By contrast, the ATP and phosphocreatine concentrations were unaltered. Conclusion: This study demonstrated the 31P FAST measurement of creatine kinase rate of ATP synthesis in rat brain with reasonable temporal resolution. Different isoflurane levels commonly used in animal models significantly alter the CK reaction rate but not ATP and phosphocreatine concentrations.
AB - Purpose: The creatine kinase rate of metabolic adenosine triphosphate (ATP) synthesis is an important metabolic parameter but is challenging to measure in vivo due to limited signal-to-noise ratio and long measurement time. Theory and Methods: This study reports the implementation of an accelerated 31P Four Angle Saturation Transfer (FAST) method to measure the forward creatine kinase (CK) rate of ATP synthesis. Along with a high-field scanner (11.7 Tesla) and a small sensitive surface coil, the forward CK rate in the rat brain was measured in ∼5 min. Results: Under 1.2% isoflurane, the forward CK rate constant and metabolic flux were, respectively, kf,CK = 0.26 ± 0.02 s-1 and Ff,CK = 70.8 ± 4.6 μmol/g/min. As a demonstration of utility and sensitivity, measurements were made under graded isoflurane. Under 2.0% isoflurane, kf,CK = 0.16 ± 0.02 s-1 and Ff,CK = 41.0 ± 4.2 μmol/g/min, corresponding to a 38% and 42% reduction, respectively, relative to 1.2% isoflurane. By contrast, the ATP and phosphocreatine concentrations were unaltered. Conclusion: This study demonstrated the 31P FAST measurement of creatine kinase rate of ATP synthesis in rat brain with reasonable temporal resolution. Different isoflurane levels commonly used in animal models significantly alter the CK reaction rate but not ATP and phosphocreatine concentrations.
KW - High fields
KW - MRS
KW - Metabolic flux
KW - Rats
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U2 - 10.1002/mrm.25136
DO - 10.1002/mrm.25136
M3 - Article
C2 - 24523049
AN - SCOPUS:84921433813
SN - 0740-3194
VL - 73
SP - 726
EP - 730
JO - Magnetic Resonance in Medicine
JF - Magnetic Resonance in Medicine
IS - 2
ER -