(A) Representative images and (B) graph showing the colocalization of NPY neurons and c-Fos (scale bar: 50 μm) of PGE2- and vehicle-treated (VH-treated) mice (n = 14/26 slices, 3–4 mice). Arrows denote colocalization between c-Fos (red) and NPY neurons (green). Mitochondrial area (C), coverage (D), aspect ratio (E), and density (F) in AgRP/NPY cells of PGE2- and vehicle-treated mice (n = 402/473 mitochondria, 14/26 cells from 3–4 mice). (G) Representative electron micrographs of mitochondria in AgRP/NPY neurons from mice treated with i.c.v. PGE2 and vehicle (scale bars: 500 nm). (H) Left: Representative trace of an NPY-GFP neuron before and during activation of Arc astrocytes by CNO and after washout. Right: MP of Arc NPY-GFP neurons (n = 5) before (Control) and during activation of Arc astrocytes by CNO and after washout. (I) Left: Representative trace of an NPY-GFP neuron before and during activation of Arc astrocytes by CNO and after washout while exposed to the EP2 receptor inhibitor PF0441894 (PF). Right: MP of Arc NPY-GFP neurons (n = 6) before PF and during activation of Arc astrocytes by CNO and after washout while exposed to the EP2 receptor inhibitor PF. (J) Food intake (1 hour) after the administration of i.p. ghrelin or vehicle. Fifteen minutes prior to the i.p. delivery of ghrelin (Ghr) or vehicle, mice were treated with i.c.v. PF or vehicle (n = 8 mice per group). Data are presented as mean ± SEM. *P ≤ 0.05, **P ≤ 0.01, and ***P ≤ 0.001 as determined by 2-tailed t test or Kolmogorov-Smirnov test for analyses of cumulative distribution. For analyses of 2 groups and 2 conditions, 2-way ANOVA with post hoc Tukey’s test was performed (J). One-way ANOVA for experiments with 3 independent groups (H and I).