L-AP4 (L-2-amino-4-phosphonobutyric acid) is a drug used in scientific research, which acts as a group-selective agonist for the group III metabotropic glutamate receptors (mGluR4/6/7/8). It was the first ligand found to act as an agonist selective for this group of mGlu receptors,[1] but does not show selectivity between the different mGluR Group III subtypes. It is widely used in the study of this receptor family and their various functions.[2][3][4][5]
^Macinnes N, Duty S (February 2008). "Group III metabotropic glutamate receptors act as hetero-receptors modulating evoked GABA release in the globus pallidus in vivo". European Journal of Pharmacology. 580 (1–2): 95–9. doi:10.1016/j.ejphar.2007.10.030. PMID18035348.
^Maciejak P, Szyndler J, Turzyńska D, Sobolewska A, Taracha E, Skórzewska A, et al. (July 2009). "The effects of group III mGluR ligands on pentylenetetrazol-induced kindling of seizures and hippocampal amino acids concentration". Brain Research. 1282: 20–7. doi:10.1016/j.brainres.2009.05.049. PMID19481536. S2CID20844494.