Figure 1. VAN Signaling Is Required for the Hyperphagic Effects of Peripheral Ghrelin, and the Ghrelin Receptor (GHSR) Is Expressed in the Nodose Ganglion and Is Reduced with Targeted RNAi.

(A–C) The left and right nodose ganglia (LNG and RNG), which house VAN cell bodies, express Ghsr mRNA in both rats (A) and mice (B) with no differences in expression between LNG and RNG in either species. Ghsr mRNA (green) is exclusively expressed in rat nodose ganglion neurons (red, neuronal marker NeuN), as demonstrated by co-localization of Ghsr and NeuN (yellow), and approximately ~73% of NeuN+ nodose ganglion neurons co-express Ghsr (C).

(D and E) After complete bilateral subdiaphragmatic vagotomy in rats (D), the hyperphagic effect of i.p. ghrelin at 40 mg/kg BW injected in the early dark cycle was abolished compared with controls (E; see also Figure S2 for comparison groups after saline injection when adjusted for body weight).

(F) VAN Ghsr expression is knocked down in rats via bilateral nodose ganglia injections of a custom-designed AAV (AAV-2 GFP-rGHSR-shRNA).

(G) Representative histology of VAN cell bodies in the nodose ganglion expressing the GHSR shRNA AAV with a green fluorescent protein (GFP) transgene.

(H) Gene expression analyses confirmed a statistically significant ~86% knockdown of the Ghsr gene in the nodose ganglion (see also Figure S3 for evaluation of Mch1r and Cb1r mRNA expression in the NG after GHSR knockdown).

All data presented as mean ± SEM.