AgRP neuron stimulation is sufficient to increase feeding during chemogenetic stimulation of PBN CGRP neurons. A, Viral injection strategy to transduce arcuate AgRP neurons and parabrachial CGRP neurons. B, Timeline of CNO administration and AgRP neuron photostimulation for each experimental trial. C, Top, Coronal diagram representing the location of PBN CGRP neurons; red square represents parabrachial region depicted in photomicrograph. Bottom, Representative image showing mCherry fluorescence in parabrachial CGRP neurons. scp, Superior cerebellar peduncle. Scale bar, 250 μm. D, Optogenetic stimulation of AgRP neurons increases food intake during CGRP neuron-mediated appetite suppression. All values represent the mean ± SEM (n = 5 animals per group). Blue background represents the 20 min photostimulation period. **p < 0.01, ****p < 0.0001, Bonferroni post hoc tests between AgRP^GFP;CGRP^hM3Dq and AgRP^ChR2;CGRP^hM3Dq experimental groups at each time point. E, Total food consumed before stimulation of AgRP neurons across conditions. F, Total food consumed during stimulation of AgRP neurons across conditions. **p < 0.01, ****p < 0.0001, Bonferroni post hoc tests between groups. G, 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.