In vitro activity: LY2119620 displays modest allosteric agonism and positively modulates the functional G protein–signaling ability of an agonist at the M2/M4 receptor subtypes by placing the M2 and M4 receptors into an active G protein–bound state. LY2119620 enhances the potency of three muscarinic acetylcholine receptor agonists, ACh, Oxo-M and iperoxo. [3H]LY2119620 can be used as a probe for the human M(2) and M(4) muscarinic receptor allosteric binding sites.

Kinase Assay: [3H]LY2119620 equilibrium binding is achieved by incubating 15 μg membranes, orthosteric ligand (100 μM), and various concentrations of [3H]LY2119620 (0.2 to 60 nM) for 1 hour at 25°C. The specific binding versus time data are fit to a one-site specific binding model, and the Bmax and Kd for the allosteric molecule are calculated for each orthosteric ligand.

Cell Assay: In [35S]GTPγS-binding experiments, LY2119620 exhibited a modest allosteric agonism of 23.2% and 16.8% at the M2 and M4 receptors, respectively. LY2119620 and ACh binding caused cooperativity factor α of 79.4 and 19.5 for the M4 receptor and the M2 receptor, respectively. The cooperativity between LY2119620 and orthosteric agonists (Iperoxo or Oxo-M) was also observed. M2 receptor simultaneously bound to LY2119620 and iperoxo. LY2119620 exhibited mild negative cooperativity with the inverse agonist NMS and strong positive cooperativity with iperoxo. LY2119620 significantly increased Bmax values without changes in Kd when cooperativity binding of [3H]LY2119620 with mAChR, suggesting a G protein-dependent process.