administration of the 5ht precursors l-tryptophan ( 25 mg/kg i.p . ) or l-5-hydroxytryptophan ( 12.5 mg/kg i.p . ) , a direct-acting 5ht agonist ( quipazine , 1 mg/kg i.p . ) or a monoamine oxidase inhibitor ( tranylcypromine , 4 mg/kg i.p . ) produced no significant changes in these behaviors in cats treated chronically with amphetamine .
C0041249
tryptophan
C0000578
l-5-hydroxytryptophan