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31 P NMR Relaxation Does Not Affect the Quantitation of Changes in Phosphocreatine, Inorganic Phosphate, and ATP Measured In Vivo During Complete Ischemia in Swine Brain
Author(s) -
Corbett Ronald J. T.,
Laptook Abbot R.
Publication year - 1993
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1993.tb03549.x
Subject(s) - phosphocreatine , inorganic phosphate , phosphate , in vivo , chemistry , relaxation (psychology) , ischemia , phosphorus 31 nmr spectroscopy , nuclear magnetic resonance , nuclear magnetic resonance spectroscopy , energy metabolism , biochemistry , endocrinology , medicine , biology , physics , microbiology and biotechnology , organic chemistry
Ischemia‐induced changes in 31 P NMR relaxation were examined in 16 piglets. NMR spectra were acquired under control conditions and during complete cerebral ischemia induced via cardiac arrest. Changes in T 1 were assessed directly in six animals during control conditions and after 30–45 min of complete ischemia when changes in brain P 1 levels had reached a plateau. The T 1 for P 1 did not change, i.e., 2.3 ± 0.5 s during control conditions versus 2.4 ± 1.0 s during ischemia. To evaluate phosphocreatine and ATP, two types of spectra, with a long (25‐s) or short (1‐s) interpulse delay time, were collected during the first 10 min of ischemia (n = 10). Both types of spectra showed the same time course of changes in phosphocreatine and ATP levels, implying that the T 1 relaxation times do not change during ischemia. There were no changes in the linewidths of phosphocreatine, ATP, or P 1 during ischemia, implying that the T * 2 values remain constant. Our results suggest that the 31 P T 1 and T * 2 for phosphocreatine, P i , and ATP do not change during ischemia, and therefore changes in 31 P NMR peak intensity accurately reflect changes in metabolite concentrations.