Brain tryptophan hydroxylation: dependence on arterial oxygen tension.
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.
D006916:5-Hydroxytryptophan / Q000032:analysis; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001593:Benzyl Compounds / Q000494:pharmacology; D001921:Brain / Q000201:enzymology* / Q000378:metabolism; D001923:Brain Chemistry / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D005263:Femoral Artery; D006834:Hydrazines / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000201:enzymology / Q000378:metabolism; D007773:Lactates / Q000378:metabolism; D008297:Male; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010100:Oxygen / Q000097:blood*; D010725:Phosphocreatine / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism; D051381:Rats; D014365:Tryptophan Hydroxylase / Q000037:antagonists & inhibitors / Q000378:metabolism
D001593:Benzyl Compounds; D006834:Hydrazines; D007773:Lactates; D011773:Pyruvates; D010725:Phosphocreatine; D002245:Carbon Dioxide; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D006916:5-Hydroxytryptophan; D006899:Mixed Function Oxygenases; D014365:Tryptophan Hydroxylase; D010100:Oxygen