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Nuclear magnetic resonance determination of flow, lactate, and phosphate metabolites during amphetamine stimulation of the rat brain
Author(s) -
Detre John A.,
Williams Donald S.,
Koretsky Alan P.
Publication year - 1990
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940030606
Subject(s) - phosphocreatine , amphetamine , chemistry , in vivo , nuclear magnetic resonance spectroscopy , metabolite , nuclear magnetic resonance , washout , phosphate , stimulation , metabolism , cerebral blood flow , endocrinology , medicine , biochemistry , dopamine , energy metabolism , biology , stereochemistry , physics , microbiology and biotechnology
The effects of amphetamine on rat cerebral blood flow, lactate, and phosphate levels were studied using in vivo nuclear magnetic resonance (NMR) spectroscopy. Proton NMR imaging was used to determine the region of brain being studied. Blood flow was estimated by detecting the washout of trifluoromethane using 19 F NMR. A dose of 20 mg/kg D‐amphetamine sulphate stimulated flow fourfold over control values for at least 1 h. Even though amphetamine stimulated a large increase in flow, there were no significant changes in levels of inorganic phosphate, ATP, phosphocreatine, pH or Mg 2+ as determined by 31 P NMR. This was true for doses of 10 and 20 mg/kg D‐amphetamine sulphate. No significant changes occurred in 1 H NMR detected levels of lactate with a 20 mg/kg dose of amphetamines. Lactate levels increased slightly 30min after administration of 10 mg/kg D‐amphetamine sulphate. The results call into question the central role of changes in levels of phosphates in coupling increased cortical activity to increases in metabolism.