In Vitro: p-Ethynylphenylalanine hydrochloride selectively and reversibly inhibits the biosynthesis of serotonin. ?p-Ethynylphenylalanine hydrochloride has a low affinity for various recombinant 5-HT receptors (5-HT1, 5-HT2, 5-HT4, 5-HT5, 5-HT6, and 5-HT7).
In Vivo: p-Ethynylphenylalanine hydrochloride (30 mg/kg; i.p.) decreases in 5-HT and 5-HIAA levels in the rat midbrain but not in tissue. ?p-Ethynylphenylalanine hydrochloride does not inhibit the aromatic amino acid decarboxylase.