3-(5-甲基-3-异噁唑基)-6-[(1-甲基-1H-1,2,3-三氮唑-4-基)甲氧基][1,2,4]三氮唑并[3,4-a]酞嗪

α5IA (LS-193,268) is a nootropic drug invented in 2004 by a team working for Merck, Sharp and Dohme, which acts as a subtype-selective inverse agonist at the benzodiazepine binding site on the GABAA receptor. It binds to the α1, α2, α3 and α5 subtypes, but shows much higher efficacy at the α5 subtype, and acts either as a weak partial agonist or inverse agonist at the other subtypes, with its partial agonist effect at α2 likely to be responsible for the lack of anxiety produced by this drug when compared to older α5-preferring inverse agonists such as L-655,708.