abstract:EMPA (N-ethyl-2-[(6-methoxy-pyridin-3-yl)-(toluene-2-sulfonyl)-amino]-N-pyridin-3-ylmethyl-acetamide) is an Orexin receptor type 2 (OX2) selective antagonist, with 900-fold selectivity in binding for OX2 over OX1."Biochemical and Electrophysiological Characterization of Almorexant, a Dual Orexin 1 Receptor (OX1)/Orexin 2 Receptor (OX2) Antagonist: Comparison with Selective OX1 and OX2 Antagonists", Pari Malherbe, Edilio Borroni, Emmanuel Pinard, Joseph G.