4-Ethynyl-L-phenylalanine hydrochloride is a selective, reversible, potent and competitive inhibitor of tryptophan hydroxylase (TPH). 4-Ethynyl-L-phenylalanine hydrochloride is a competitive inhibitor with regard to the substrate tryptophan, with a Ki of 32.6 μM. 4-Ethynyl-L-phenylalanine hydrochloride selectively and reversibly inhibits the biosynthesis of serotonin[1].
4-Ethynyl-L-phenylalanine hydrochloride (30 mg/kg; i.p.) decreases in 5-HT and 5-HIAA levels in the rat midbrain but not in tissue[1].4-Ethynyl-L-phenylalanine hydrochloride is not inhibiting the aromatic amino acid decarboxylase[1].4-Ethynyl-L-phenylalanine hydrochloride has a low affinity for various recombinant 5-HT receptors[1]. Animal Model: Male Sprague-Dawley rats (200 g)[1]
[1]. Stokes AH, et al. p-ethynylphenylalanine: a potent inhibitor of tryptophan hydroxylase. J Neurochem. 2000 May;74(5):2067-73.