LY-178210, also known as LY-228729 or as 4,ñ-methylene-5-carboxamido-DPT, is a selective and highly potent serotonin 5-HT<sub>1A</sub> receptor partial agonist. It has an affinity (K<sub>i</sub>) of 0.67nM for the serotonin 5-HT<sub>1A</sub> receptor. The drug has high selectivity for this receptor over 12other assessed targets, including the serotonin 5-HT<sub>1D</sub>, 5-HT<sub>2A</sub>, 5-HT<sub>2C</sub>, and 5-HT<sub>3</sub> receptors among others (K<sub>i</sub> = âÂÂ¥380âÂÂ4,000nM). LY-178210 is a tricyclic simplified or partial ergoline and is structurally related to LSD. It was described as a potential clinical development candidate but was not further developed and was never marketed. The drug was first reported in the scientific literature by 1990.