Dopamine regulation of extracellular glutamate in the nucleus accumbens.

The capacity of dopamine to alter extracellular glutamate in the nucleus accumbens was examined by passing 1, 10 and 100 microM of amphetamine, the D(2/3) agonist, quinpirole, or the D1 agonist, SKF-82958 through a microdialysis probe. It was found that amphetamine and quinpirole produced a dose-dependent reduction in the basal levels of extracellular glutamate, while SKF-82958 was without significant effect. The capacity of the D1 antagonist, SCH-23390 (1.0 mg/kg, i.p.) or the D2 antagonist, sulpiride (10 mg/kg, i.p.) to block the reduction in extracellular glutamate by amphetamine (100 microM) was examined. Both SCH-23390 and sulpiride prevented the reduction in extracellular glutamate by amphetamine. The data indicate that, similar to the striatum, glutamate release in the nucleus accumbens is modulated by presynaptic dopamine receptors.