Figure 4.

Blunted suppression of food intake in response to CCK on an HFHS diet is reinstated by concomitant chemogenetic activation of PVN^OT neurons

(A) Cumulative food intake of SC diet-fed control mice upon vehicle versus CCK (20 μg/kg BW, i.p.) plus CNO (1 mg/kg BW, i.p.). Data are presented as mean ± SEM. Shown is corresponding latency to feed (bottom). ^∗∗p < 0.01, ^∗p < 0.05. n = 5 mice in a cross-over design (two-way ANOVA and paired Student’s t test [bottom]).

(B) Cumulative food intake of HFHS diet-fed control mice upon vehicle versus CCK (20 μg/kg BW, i.p.) plus CNO (1 mg/kg BW, i.p.). Data are presented as mean ± SEM. Shown is corresponding latency to feed (bottom). n = 8 mice in a cross-over design (two-way ANOVA and paired Student’s t test [bottom]).

(C) Cumulative food intake of HFHS diet-fed hM3Dq^OT+/PVN mice upon vehicle versus CCK (20 μg/kg BW, i.p.) plus CNO (1 mg/kg BW, i.p.). Data are presented as mean ± SEM. Shown is corresponding latency to feed (bottom). ^∗∗p < 0.01, n = 8 mice in a cross-over design (two-way ANOVA and paired Student’s t test [bottom]).

(D) Representative confocal micrographs depicting neuronal activation by means of nuclear c-Fos immunoreactivity (green) in virally transduced PVN^OT neurons (mCherry⁺, red). Scale bar, 50 μm.

(E) Quantification of activated (c-Fos⁺) virally transduced PVN^OT neurons (mCherry⁺) upon CCK (20 μg/kg BW, i.p.) plus CNO (1 mg/kg BW, i.p.) injections in HFHS diet-fed hM3Dq^OT+/PVN mice or control mice. ^∗∗∗∗p < 0.0001, n = 4 mice/3–8 hemisections (one-way ANOVA).

(F) Quantification of activated (c-Fos⁺) PVN neurons overall upon CCK (20 μg/kg BW, i.p.) plus CNO (1 mg/kg BW, i.p.) injections in HFHS diet-fed hM3Dq^OT+/PVN mice or control mice. ^∗∗p < 0.01, ##p < 0.01, n = 4 mice/3–8 hemisections (one-way ANOVA).

(G) Representative confocal micrographs depicting neuronal activation (c-Fos⁺, green) across the NTS of hM3Dq^OT+/PVN mice or control mice following either CNO or CNO+CCK; insets display co-localization with TH (gray). Scale bar, 100 μm and 20 μm (inset).

(H) Quantification of activated (c-Fos⁺) NTS neurons upon CCK (20 μg/kg BW, i.p.) plus CNO (1 mg/kg BW, i.p.) injections in HFHS diet-fed hM3Dq^OT+/PVN mice or control mice. ^∗∗p < 0.01. n = 4 mice/3–8 hemisections (one-way ANOVA).

(I) Relative BW changes of male wild-type mice and tamoxifen-inducible global OTR^−/− mice, all fed an HFHS diet and treated bidaily with either OT (500 nmol/kg BW, s.c.), A-71623 (30 nmol/kg BW, i.p.), or their combination. Data are presented in percent of initial BW as mean ± SEM. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001. n = 6–8 mice (two-way ANOVA).

(J) Cumulative food intake of the cohort shown in (H). Data are presented as mean ± SEM. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001. n = 6–8 mice (two-way ANOVA).

(K) Changes in body composition of the cohort shown in (H) and (I) at the end of study. Data are presented relative to initial body composition as mean ± SEM. ^∗∗p < 0.01, ^∗∗∗∗p < 0.0001. n = 5–7 mice (unpaired Student’s t test).