The mGlu5 receptor antagonist MTEP attenuates opiate self-administration and cue-induced opiate-seeking behaviour in mice

The mGlu5 receptor (mGluR5) has been implicated in the rewarding effect of various drugs of abuse and drug-seeking behaviour. In the present study we investigated the impact of antagonism of mGluR5 with the selective negative allosteric, modulator 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) on operant self-administration of morphine as well as cue-induced drug-seeking in adult CD1 mice. Administration of MTEP (20 mg/kg, i.p.) attenuated operant responding for morphine (0.1 mg/kg/infusion) and cue-induced morphine-seeking after a period of forced abstinence. Collectively, these data implicate mGluR5 in the reinforcing effects of opiates and support the proposition that mGluR5 is a potential therapeutic target for treatment of drug addiction.