PCPA methyl ester hydrochloride (4-Chloro-DL-phenylalanine methyl ester hydrochloride), a reversible tryptophan hydroxylase inhibitor, is a serotonin (5-HT) synthesis inhibitor. PCPA methyl ester hydrochloride crosses the blood brain barrier and reduces 5-HT central availability[2].In Vivo: PCPA methyl ester hydrochloride (250-500 mg/kg; oral administration; daily; for 8 weeks) treatment significantly decreases serotonin levels in both hippocampus and cortex.
In C57BL/6 elite male mice, 5-HT levels decreased by 85% and 55% in the hippocampus of mice treated with oral or ip PCPA methyl ester hydrochloride, respectively, whereas in the prefrontal cortex, 5-HT levels decreased by 65% (oral) and 50% (ip).