Abstract
The accumulation of cerebral 5-hydroxytryptophan after decarboxylase inhibition was decreased in rats maintained at arterial O(2) tensions below 60 mm-Hg. In contrast, brain lactate was stable above 40 mm-Hg and brain adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate were unchanged above 30 mm-Hg. There was a linear correlation of brain 5-hydroxytryptophan accumulation to cerebral venous O(2) tension. Cerebral tryptophan hydroxylase appears to have a poor affinity for oxygen and to be affected by slight hypoxia. The resultant decreases in monoamine neurotransmitter metabolism may explain the behavioral changes of mild oxygen deprivation.
MeSH terms
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5-Hydroxytryptophan / analysis
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Adenosine Diphosphate / metabolism
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Adenosine Monophosphate / metabolism
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Adenosine Triphosphate / metabolism
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Animals
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Benzyl Compounds / pharmacology
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Brain / enzymology*
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Brain / metabolism
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Brain Chemistry / drug effects
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Carbon Dioxide / blood
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Femoral Artery
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Hydrazines / pharmacology
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Hydrogen-Ion Concentration
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Hypoxia / enzymology
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Hypoxia / metabolism
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Lactates / metabolism
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Male
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Mixed Function Oxygenases / metabolism*
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Oxygen / blood*
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Phosphocreatine / metabolism
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Pyruvates / metabolism
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Rats
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Tryptophan Hydroxylase / antagonists & inhibitors
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Tryptophan Hydroxylase / metabolism
Substances
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Benzyl Compounds
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Hydrazines
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Lactates
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Pyruvates
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Phosphocreatine
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Carbon Dioxide
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Adenosine Monophosphate
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Adenosine Diphosphate
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Adenosine Triphosphate
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5-Hydroxytryptophan
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Mixed Function Oxygenases
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Tryptophan Hydroxylase
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Oxygen