Figure 2. DCC receptors within dopamine neurons determine their fine axonal architecture in the mPFC.

(A) Infection strategy for labeling dopamine neurons with eYFP. (B) Right panel: Representative labeling of dopamine neurons in the ventral tegmental area. Left panel: single eYFP-positive mPFC dopamine axon. Inset: Neurolucida tracing of eYFP labeled axon. (C) Neurolucida tracings of representative dopamine axons from the cingulate (Cg1) and prelimbic (PrL) subregions of the mPFC. (D) Dcc^lox/+DAT^Cre mice have shorter mPFC dopamine axons (Two-way mixed design ANOVA, main effect of genotype, F_{(1, 6)} = 6.028, p = 0.0494; main effect of subregion, F_{(1, 6)} = 10.11, p = 0.0191; no interaction, F_{(1, 6)} = 0.04470, p = 0.8396; n = 4 per group). (E) Dcc^lox/+DAT^Cre mice have less complex mPFC dopamine axons (Two-way mixed design ANOVA, main effect of genotype, F_{(1, 6)} = 9.845, p = 0.0201; no effect of subregion, F_{(1, 6)} = 0.6213, p = 0.4606; no interaction, F_{(1, 6)} = 2.097, p = 0.1978. n = 4 per group. Inset: ACI calculation (33)). (F) Representative Neurolucida tracings of mPFC dopamine axons, circles represent varicosities. (G) mPFC dopamine axons of Dcc^lox/+DAT^Cre mice have greater density of varicosities (Two-way mixed design ANOVA, main effect of genotype, F_{(1, 6)} = 11.24, p = 0.0154; no effect of subregion, F_{(1, 6)} = 0.0000004733, p = 0.9983; no interaction, F_{(1, 6)} = 3.056, p = 0.1310. Dcc^lox/+DAT^Cre n = 4; Wild-type n = 4). (H) Model of fine mPFC dopamine axonal architecture.