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 .
C0041249
tryptophan
C0000578
5-htp