Figure 8.

Acute activation of Nos1^PVH neurons increases energy expenditure. WT+AAV-hM3Dq, Sim1-Cre+AAV-hM3Dq, and Nos1-iCre or OXT-iCre+AAV-hM3Dq mice were injected with vehicle (white bars) or CNO (black bars). A, B, E, Activation of Sim1^PVH, Nos1^PVH or OXT^PVH neurons increases average oxygen consumption (A, B) and total activity (E) over 4 h following injection. C, D, A second cohort of CNO-naive mice also shows a trend toward increased 4 h average VO₂ in response to activation of OXT^PVH neurons, while baseline VO₂ is unchanged compared with WT+3Dq or OXT-iCre mice without 3Dq injections (WT, n = 5; Sim1-Cre, n = 4; Nos1-iCre, n = 4; OXT-iCre cohort 1, n = 10; WT cohort 2, n = 4; OXT-iCre+3Dq cohort 2, n = 4; OXT-iCre, n = 4). F, To determine potential activity-independent changes in VO₂, VO₂ was determined in Sim1-Cre+3Dq and Nos1-iCre+3Dq mice before and after CNO treatment, at time points when locomotor activity was approximately matched at activity levels below a threshold value of 300 counts/h (bars indicate average values ± SEM, line segments indicate individual mice; Sim1, n = 4; Nos1, n = 4). Average values ± SEM are shown. *p < 0.05, **p < 0.01, ***p < 0.001 compared with vehicle values. Significance was determined using two-tailed paired t test within groups or unpaired t test between groups.