Fig 1: Immunofluorescence double staining of c-Fos and enkephalin in forebrain-WT and forebrain-A2AR KO mice after saline or cocaine treatment.(A) Representative merged images of immunofluorescence double staining of c-Fos (red) with enkephalin (Enk, green) in cocaine- vs. saline-treated fb-A2AR KO and fb-WT mice. (B) Quantitative analysis demonstrating the percentage of total c-Fos positive [c-Fos(+)]cells out of the total cells. (C) Quantitative analysis showing the percentage of c-Fos and Enk double positive [c-Fos(+)Enk(+)] stained cells out of the total cells. (D) Quantitative analysis demonstrating the percentage of c-Fos positive but Enk negative [c-Fos(+)Enk(-)] cells out of the total cells. Data in the bar graphs are mean ± SEM, n = 6-10 per group. * p< 0.05, vs. groups of same genotype with saline treatment; # p< 0.05 vs. cocaine-treated WT groups. ? p< 0.05, vs. saline-treated fb-A2AR group. Scale bar = 50 µm. Yellow arrows indicate neurons with c-Fos positive but Enk negative [c-Fos(+)Enk(-)] staining; Red arrows indicate neurons with c-Fos and Enk double positive [c-Fos(+)Enk(+)] staining.