Lu AF21934 is a brain-penetrant and selective mGlu4 receptor positive allosteric modulator (IC50: 500 nM, human).

Lu AF21934 treatment shows a dose-dependent anxiolytic-like effect in the stress-induced hyperthermia, four-plate, and marble-burying tests. The anti-hyperthermic effect of Lu AF21934 (5 mg/kg) in the SIH test is inhibited by the benzodiazepine receptor antagonist flumazenil (10 mg/kg) and is not serotonin-dependent. Lu AF21934 does not produce antidepressant-like effects in the tail suspension test in mice; however, it decreases the basal locomotor activity of mice that are not habituated to activity cages.

The receptor-expressing CHO cells are seeded into 24-well plates at a density of 4×104 cells/well and cultured for 1 day. The cells are then incubated with [5,6,8,9,11,12,14,15-3H]arachidonic acid (11 kBq/well) for 1 day and ished with DMEM supplemented with 20 mM HEPES and 0.2% BSA. The cells are then preincubated with the compounds (Sufugolix) at 37 °C for 60 min and the reaction is started by addition of LHRH (1 nM). After incubation at37 °C for 40 min, radioactivity in the medium is measured with a liquid scintillation counter[1].