Previous studies indicate that
metabotropic glutamate receptor type 2/3 (
mGluR2/3) has a key role in the rewarding properties of
morphine-induced conditioning place preference (
CPP). Group II
mGluR2/3 agonists are offered as a
drug addiction treatment. The nucleus accumbens (NAc), which is one of the important areas involved in the reward circuitry, also expresses these receptors. In this study, we evaluated the effects of
mGluR2/3 agonist,
LY379268, on the extinction and reinstatement of
morphine-induced
CPP, following its microinjection into the NAc. Adult male Wistar rats (220-250 g) were implanted bilaterally by two separate
cannulae into the NAc. After the acquisition of
morphine CPP, different doses of
LY379268 (0.3, 1 and 3 µg/0.5 μl saline) were microinjected into the NAc every day during the extinction period and, in a different set of experiments, on the reinstatement test day, 60 min before the infusion of a priming dose of
morphine (1 mg/kg; subcutaneous). Thereafter, the animals were tested for place preference by the Ethovision software. The intra-accumbal injection of the
mGluR2/3 agonist,
LY379268, significantly decreased the extinction latencies and reinstatement of
morphine-induced
CPP at higher doses. It seems that the NAc might be a functional region for
mGluR2/3 to play a regulatory role for decreasing drug-seeking behavior in rats. Furthermore, it can be said that
mGluR2/3 agonists have a potential role in the treatment of drug-seeking behaviors.