Selective positive allosteric modulator of M4 receptor (KB = 200 nM, α = 35); increases the potency of acetylcholine by 40-fold. Exhibits no effect at hM1/3/5 receptors and a small effect at hM2 (KB = 1 μM α = 3.7). Potentiates other full and partial orthosteric agonists, including Carbachol, Oxotremorine-M, and McN-A343. Does not affect binding of antagonist NMS. Active in vivo. Antipsychotic. α indicates the degree of allosteric enhancement when both orthosteric and allosteric sites are occupied (derived from the allosteric ternary complex model).

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