to test whether this correlation was causal , central catecholamines were increased by the intraperitoneal administration of l-3,4-dihydroxyphenylalanine ( l-dopa ) , 10 -- 40 mg/kg ) after inhibition of extracerebral l-amino acid decarboxylase .
C0007412
catecholamines
C0013023
dihydroxyphenylalanine