A-841720 is a noncompetitive antagonist of the group 1 metabotropic glutamate receptor mGluR1 with an IC value of 10.7 nM for inhibition of L-glutamate-induced calcium release in 1321 N1 cells. It is selective for mGluR1 over mGluR5 (IC = 343 nM) as well as mGluR2, mGluR4, and mGluR7, where it does not inhibit agonist-induced calcium release in HEK293 cells. It is also selective for mGluR1 over a panel of other G-coupled protein receptors as well as ligand- and voltage-gated ion channels at a concentration of 10 µM. A-841720 dose-dependently inhibits complete Freund's adjuvant-induced inflammatory pain (ED = 23 µmol/kg) and sciatic nerve injury-induced mechanical allodynia (ED = 28 µmol/kg) in rats. It also enhances cocaine seeking in mice after a prolonged abstinence following a single conditioning session when administered at a dose of 10 mg/kg per day.