UBP 302, the S enantiomer, is a potent and selective GluK1 (GluR5)-subunit containing kainate receptor antagonist (apparent Kd=402 nM), and displays very little affinity on GluK2 (GluR6) kainate receptors. Anxiolytic effects[1][2][3].
[1]. More JC, et al. Characterisation of UBP296: a novel, potent and selective kainate receptor antagonist. Neuropharmacology. 2004 Jul;47(1):46-64. [2]. Dolman NP, et al. Synthesis and pharmacology of willardiine derivatives acting as antagonists of kainate receptors. J Med Chem. 2005 Dec 1;48(24):7867-81. [3]. Apland JP, et al. The limitations of diazepam as a treatment for nerve agent-induced seizures and neuropathology in rats: comparison with UBP302. J Pharmacol Exp Ther. 2014 Nov;351(2):359-72.