Lu AF21934

Lu AF21934 is a selective and brain-penetrant mGlu4 receptor positive allosteric modulator with an EC₅₀ of 500 nM for mGlu4 receptor^[1]. IC50 & Target: EC50: 500 nM (hmGlu4)^[1] In Vivo: 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^[1]. Lu AF21934 (0.5-5 mg/kg sc) does not influence tremor but at doses of 0.5 and 2.5 mg/kg reverses harmaline-induced hyperactivity. Lu AF21934 at a dose of 2.5 mg/kg potentiates the inhibitory influence of harmaline on the exploratory activity and AP1 during the first 30 min of the measurement and counteracts the harmaline-increased basic activity during the period of 30-90 min^[2]. Lu AF21934 (0.1-5 mg/kg) dose-dependently inhibits hyperactivity induced by MK-801 or amphetamine. It also antagonizes head twitches and increases frequency of spontaneous excitatory postsynaptic currents in brain slices, induced by DOI^[3].