Figure 6.

Brief D₁ receptor stimulation increases surface and synaptic GluR1 expression by DA neurons in VTA-PFC cocultures. A, VTA-PFC cocultures were treated with media (control group), the D₂ agonist quinpirole (Quin; 1 μm, 10 min), DA (1 μm, 10 min), or the D₁ agonist SKF 81297 (SKF; 1 μm, 10 min). Both DA and SKF 81297 significantly increased surface GluR1 area and GluR1 synaptic incorporation compared with the control group (n = 18–24; Dunn's test, *p < 0.05), whereas quinpirole had no effect on either measure (ANOVA, p > 0.05). DA and SKF 81297 also increased nonsynaptic GluR1 (data not shown). B, VTA-PFC cocultures were treated with media, SKF 81297 (1 μm, 10 min), SCH 23390 (SCH, 10 μm, 10 min), or SCH+SKF (after 5 min preincubation with SCH 23390, SKF 81297 was added for 10 min). SCH 23390 alone had no effect on surface GluR1 area or GluR1 synaptic incorporation, but completely blocked the effect of SKF 81297 on these measures (n = 19–24; Dunn's test, *p < 0.05). C, VTA-PFC cocultures were treated with media, DA (1 μm, 10 min), SCH 23390 (10 μm, 10 min), or SCH+DA (after 5 min preincubation with SCH 23390, DA was added for 10 min). SCH 23390 alone had no effect on surface GluR1 area or GluR1 synaptic incorporation, but completely blocked the effect of DA on these measures (n = 18–19; Dunn's test, *p < 0.05).