Stimulation of projections from AgRP neurons to parabrachial neurons increases feeding following administration of noninflammatory anorexigenic compounds. A, Injection strategy in AgRP^Cre/+ mice for AgRP-to-PBN projection experiments. B, Stimulation of AgRP neuron projections has no effect on baseline food intake following administration of saline. Blue background represents the 20 min photostimulation period. C–F, Stimulation of AgRP neuron projections increases food intake following administration of amylin (C), CCK (D), and LiCl (E), but not following administration of LPS (F). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, Bonferroni post hoc tests between groups. G, Total food consumed during stimulation of AgRP neurons across conditions. All values represent the mean ± SEM, black dots represent individual animals (n = 5 animals per group). **p < 0.01, ***p < 0.001, Bonferroni post hoc tests between groups. H, Injection strategy in AgRP^Cre/+; Calca^Cre/+ double knock-in mice for AgRP-to-PBN projection experiments with hM₃Dq-mediated stimulation of CGRP neurons. I, Stimulation of AgRP neuron projections increases food intake following injection of CNO. **p < 0.01, ***p < 0.001, Bonferroni post hoc tests between groups. J, Representative histological images showing coincident hM3Dq-mCherry (red) and Fos (green) expression in CGRP neurons following injection of CNO in ChR2-mCherry- or GFP-transduced animals and photostimulation of AgRP neurons. Scale bar, 250 μm. K, AgRP neuron projections throughout the lateral parabrachial nucleus. Top, Coronal diagram representing the location of CGRP neurons; red square represents parabrachial region depicted in photomicrographs. Bottom, Representative images showing hM₃Dq-mCherry transduced CGRP neurons and GFP-transduced AgRP fiber projections in the lateral parabrachial nucleus. scp, Superior cerebellar peduncle. Light blue dashed line at top of bottom image shows approximate location of tips of fiber-optic implants. Scale bar, 250 μm.