L-AP4 (L-APB) monohydrate is a potent and specific agonist for the group III mGluRs, with EC50s of 0.13, 0.29, 1.0, 249 μM for mGlu4, mGlu8, mGlu6 and mGlu7 receptors, respectively[1][2].

L-AP4 (5-30 μg, intrathecal inhection 4-5 days) significantly increases the paw withdrawal threshold in response to application of von Frey filaments in eight nerve-ligated rats in a dose-dependent manner. Intrathecal administration of different doses of L-AP4 is not associated with any evident motor dysfunction[2].Intrathecal injection of 30 μg of L-AP4 does not significantly alter the paw withdrawal latency in these normal rats[2].Topical application of 5 to 50 μM L-AP4 to the spinal cord significantly inhibited the evoked response of neurons to touch, pressure, pinch, and von Frey filaments in a concentration-dependent fashion[2]. Animal Model: Rats.[2]

[1]. Selvam C, et al. Increased Potency and Selectivity for Group III Metabotropic Glutamate Receptor Agonists Binding at Dual sites. J Med Chem. 2018 Mar 8;61(5):1969-1989. [2]. Chen SR, et al. Distinct roles of group III metabotropic glutamate receptors in control of nociception and dorsal horn neurons in normal and nerve-injured Rats. J Pharmacol Exp Ther. 2005 Jan;312(1):120-6.