UH-301, also known as (S)-5-fluoro-8-hydroxy-2-(dipropylamino)tetralin ((S)-5-FHDPAT), is a drug and research chemical widely used in scientific studies. It acts as a selective serotonin 5-HT<sub>1A</sub> receptor silent antagonist. It is structurally related to 8-OH-DPAT. UH-301 was found to produce a head-twitch response in mice which is usually typical of 5-HT<sub>2A</sub> agonist drugs, and has subsequently been used to investigate how 5-HT<sub>1A</sub> receptor activity modulates 5-HT<sub>2A</sub> receptors downstream.