ACPT-II is a general competitive antagonist of metabotropic glutamate (mGlu) receptors. The KB values for mGlu1a, mGlu2, and mGlu4a receptors are 115, 88, and 77 μM, respectively. It binds to the large extracellular domain called a Venus flytrap module, where agonists bind. ACPT-II is a stereoisomer of the group III mGlu receptor-selective antagonist, ACPT-I.
