3-(3-chlorophenyl)-1-(1-methyl-4-oxo-5H-imidazol-2-yl)urea hydrate

Fenobam is a noncompetitive antagonist and inverse agonist of metabotropic glutamate receptor 5 (mGluR5) that binds to an allosteric site. It inhibits intracellular calcium mobilization induced by the glutamate analog quisqualate in HEK293 cells expressing the human receptor (IC₅₀ = 58 nM) and inhibits basal activity of mGluR5 in a cell-based assay (IC₅₀ = 84 nM). Fenobam (10 and 30 mg/kg) reduces stress-induced hyperthermia in mice and increases drinking time in the Vogel conflict test in rats when administered at a dose of 30 mg/kg, indicating anxiolytic-like activity. It induces analgesia in the formalin test in mice when administered at a dose of 30 mg/kg.

Sedative-hypnotic.

mGluR5: 84 nM (IC₅₀); human mGluR5: 31 nM (Kd); rat mGluR5: 54 nM (Kd)

[1] RICHARD H P PORTER. Fenobam: a clinically validated nonbenzodiazepine anxiolytic is a potent, selective, and noncompetitive mGlu5 receptor antagonist with inverse agonist activity.[J]. Journal of Pharmacology and Experimental Therapeutics, 2005, 315 2: 711-721. DOI: 10.1124/jpet.105.089839
[2] MICHAEL C MONTANA. Metabotropic glutamate receptor 5 antagonism with fenobam: examination of analgesic tolerance and side effect profile in mice.[J]. ACS Catalysis , 2011: 1239-1250. DOI: 10.1097/aln.0b013e318238c051