the present study was aimed to clarify , by use of the passive immunization method , the involvement of endogenous vasoactive intestinal polypeptide ( vip ) and peptide histidine isoleucine amide ( phi ) -like peptides in the stimulation of prl-like immunoreactive material release induced by 5-hydroxy-l-tryptophan ( 5htp ) , a serotonin precursor .
C0041249
tryptophan
C0000578
5htp