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. 2020 Feb 25;117(10):5502–5509. doi: 10.1073/pnas.1916132117

Fig. 4.

Fig. 4.

Gpr151–KO mice show reduced sensitivity to nicotine and self-administer more nicotine at a high dose. (A) Nicotine-induced hypolocomotion (0.65 mg/kg, i.p.) is significantly diminished in Gpr151–KO mice (n = 7 per genotype; repeated-measures (RM) two-way ANOVA, Bonferroni multiple comparisons *P < 0.05, **P < 0.01 for genotype; Tukey’s multiple comparisons test, ###P < 0.001 for time in both groups). (B) Hypolocomotion is observed at the higher 2 doses of nicotine (0.65 and 1.5 mg/kg) in WT mice, WT mice injected with AAV2.1–scramble–shRNA (scramble) and in Gpr151–KO mice injected with AAV2.1–CAG–Gpr151 (rescue) in the MHb, but not in Gpr151–KO mice and in WT mice injected with AAV2.1–shRNA against Gpr151 (shRNA) in the MHb. (n = 7–8 per genotype, RM two-way ANOVA, Tukey’s multiple comparison test, *P < 0.05, **P < 0.01, ***P < 0.001 for genotype; ##P < 0.01, ###P < 0.001 compared to 0.35 mg/kg nicotine within the same genotype). (C) Average number of food rewards after injection of saline or nicotine (1 mg/kg, s.c.). Gpr151–KO mice are resistant to the anorectic effect of nicotine (n = 10 per group, RM two-way ANOVA, Bonferroni's multiple comparisons test, **P < 0.01 compared to WT). (D) Gpr151–KO mice earned significantly more nicotine infusions at the higher nicotine dose (0.4 mg/kg) (n = 4–8, RM two-way ANOVA, Bonferroni's multiple comparisons test, **P < 0.01 compared to WT). (E) Total amount of nicotine self-administered at each dose (n = 4–8, RM two-way ANOVA, Bonferroni's multiple comparisons test, ***P < 0.001 compared to WT). Gpr151–KO mice self-administer a significantly higher amount of nicotine at the highest 0.4 mg/kg/session dose. (F) Reexpression of GPR151 in the MHb and IPN terminals of Gpr151–KO mice injected with AAV2.1–Gpr151 visualized by GPR151 immunoreactivity and comparison with Gpr151–KO mice injected with AAV2/1–EGFP control virus. (Scale bar, 500 μm.) (G) At the highest nicotine dose (0.4 mg/kg/session), Gpr151–KO mice injected with AAV2.1–Gpr151 rescue virus self-administered less nicotine (Left) to similar levels as WT (Right) (n = 6–12, unpaired t test, **P < 0.01). Data are represented as mean ± SEM. See SI Appendix, Table S3 for details of statistical analysis. n.s., not significant.