The effects of acute hypercapnia on cerebral indole amine metabolism.
The effects of 1-h exposure to hypercapnia (PaCO2, 90-110 MMHg) on cerebral indole amine metabolism were studied in rats by measurement of cerebral hemisphere contents of tryptophan, 5-hydroxytryptophan (5-HTP), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA), 5-HIAA content was increased after 1-h exposure to hypercapnia, whereas tryptophan, 5-HTP, and 5-HT remained unchanged from control. The accumulation of 5-HTP after decarboxylase inhibition with 3-hydroxybenzyl hydrazine was increased in hypercapnic rats and indicated an increased activity of tryptophan hydroxylase. During the 1-h exposure to hypercapnia there was increased accumulation of 5-HT after monoamine oxidase inhibition with pargyline and increased accumulation of 5-HIAA arter probenecid. The results indicate an increased synthesis and degradation of indole amines in acute hypercapnia.
D006916:5-Hydroxytryptophan / Q000378:metabolism; D000588:Amines / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D006834:Hydrazines / Q000494:pharmacology; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D006900:Hydroxylation; D006935:Hypercapnia / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism*; D008297:Male; D010293:Pargyline / Q000494:pharmacology; D011339:Probenecid / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000378:metabolism; D014364:Tryptophan / Q000378:metabolism
D000588:Amines; D006834:Hydrazines; D007211:Indoles; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan; D010293:Pargyline; D006916:5-Hydroxytryptophan; D011339:Probenecid