p-Ethynylphenylalanine (4-Ethynyl-L-phenylalanine) is a potent, selective, reversible and competitive inhibitor of tryptophan hydroxylase (TPH) , with a K i of 32.6 μM In Vitro p-Ethynylphenylalanine selectively and reversibly inhibits the biosynthesis of serotonin. p-Ethynylphenylalanine has a low affinity for various recombinant 5-HT receptors (5-HT 1 , 5-HT 2 , 5-HT 4 , 5-HT 5 , 5-HT 6 , and 5-HT 7 ). MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo p-Ethynylphenylalanine (30 mg/kg; i.p.) decreases in 5-HT and 5-HIAA levels in the rat midbrain but not in tissue . p-Ethynylphenylalanine does not inhibit the aromatic amino acid decarboxylase . MCE has not independently confirmed the accuracy of these methods. They are for reference only. Animal Model: Male Sprague-Dawley rats (200 g) Dosage: 30 mg/kg Administration: Intraperitoneal injection Result: Decreased in 5-HT and 5-HIAA levels in the rat midbrain. Form:Solid IC50& Target:Ki: 32.6 μM (TPH)