the mode of actions of 5-hydroxytryptamine ( 5-ht ) and its derivatives , tryptophan ( tp ) , 5-hydroxytryptophan ( 5-htp ) and 5-hydroxyindole acetic acid ( 5-hiaa ) was studied on the isolated , blood-perfused small intestine and isolated ileum strip of rats .
C0041249
tryptophan
C0000578
5-htp