(a) Protocol for Cre-dependent induction of BoNT/B in tanycytes followed by the injection of recombinant TAT-Cre or vehicle into the third ventricle of BoNTB-EGFPloxP-STOP-loxP mice. (b-e) Representative photomicrographs of c-Fos immunohistochemistry in the hypothalamus of control (b, c) and iBot (d, e) mice 1h after intraperitoneal injection of saline (left panels) or liraglutide (90 nmol/Kg, right panels). AHN: anterior hypothalamic nucleus; ARH: arcuate nucleus of the hypothalamus; DMH: dorsomedial hypothalamic nucleus; LHA: lateral hypothalamic nucleus; PVH: paraventricular nucleus of the hypothalamus; TUB: tuberal nucleus; ZI: zona incerta. Scale bar 200 μm. (f) Quantification of the number of c-Fos positive cells in mouse hypothalamic sections 1 hour after intraperitoneal injection of either saline (black, grey) or liraglutide (0,1 mg/kg) (green, blue) in control (black and green) and iBot mice (grey and blue). (n = 3, 4, 3, 4 animals per group; 6 to 7 sections per animal). PVH: two-way ANOVA, genotype: F(1, 10)= 6.96, p = 0.024; treatment: F(1, 10)= 0.586, p = 0.024; interaction: F(1, 10)= 6.502, p = 0.0289. Fisher’s LSD post hoc test, control saline vs. control liraglutide, p = 0.0410 and control liraglutide vs. iBot liraglutide, p = 0.0027. LHA: two-way ANOVA, genotype: F(1, 10)= 15.54, p = 0.0028; treatment: F(1, 10)= 5.19, p = 0.045; interaction: F(1, 10)= 4.468, p = 0.0607. Fisher’s LSD post hoc test, control saline vs. control liraglutide, p = 0.011 and control liraglutide vs. iBot liraglutide, p = 0.0009. DMH: two-way ANOVA, genotype: F(1, 10)= 5.21, p = 0.0456; treatment: F(1, 10)= 0.1, p = 0.756; interaction: F(1, 10)= 3.827, p = 0.078. Fisher’s LSD post hoc test, control liraglutide vs. iBot liraglutide, p = 0.0089. ZI: two-way ANOVA, genotype: F(1, 10)= 2.25, p = 0.164; treatment: F(1, 10)= 0.03, p = 0.871; interaction: F(1, 10)= 6.15, p = 0.032. Fisher’s LSD post hoc test, control liraglutide vs. iBot liraglutide, p = 0.0124. Data are expressed as means ± SEM. *p < 0.05; ** p < 0.01, control saline vs. control liraglutide; # p < 0.05; ## p < 0.01, control liraglutide vs. iBot liraglutide.