Supplemental Fig. 2 from To eat or not to eat: ontogeny of hypothalamic feeding controls and a role for leptin in modulating life-history transition in amphibian tadpoles

Functional leptin signaling in tadpole brain increased during metamorphosis. We investigated changes in functional leptin signaling in the anterior preoptic area (POA) of tadpole brain during metamorphosis by analyzing rxLeptin-induced phospho-STAT3 immunoreactivity (pSTAT3-ir). A. Anatomical drawings of the brain regions analyzed, after Tuinhof et al. [1]. Abbreviations: Apl – amygdala pars lateralis, BNST – bed nucleus of the stria terminals, CeA – central amygdala, MeA – medial amygdala, dp – dorsal pallium, lp – lateral pallium, mp – medial pallium, nII – cranial nerve II, POa – preoptic area. B. Tadpoles were given i.c.v. injections of 0.6% saline or rxLeptin (20 ng/g*BW) and killed one hr later for immunochistochemistry for pSTAT3-ir (see Supplemental Methods). Injection of rxLeptin, but not saline caused the appearance of pSTAT3-ir in the regions of the tadpole parvocellular and the magnocellular POa. The scale bar in the top left image equals 50 m and applies to all photomicrographs in the panels. Labels: pPOa – parvocellular anterior preoptic area, mPOa – magnocellular preoptic area. C. Changes in mean nuclei count of pSTAT3-ir cells in the magnocellular and parvocellular divisions of the tadpole POA during metamorphosis. We counted the number of pSTAT3-ir nuclei following i.c.v. injection of rxLeptin as described in the Materials and Methods. Shown are the means±SEM (n=6-8/developmental stage). We saw statistically significant changes in pSTAT3-ir during metamorphosis in both regions of the POa (parvocellular: F(4,31)=30.589, P<0.0001; magnocellular: F(4,29)=4.093, P=0.009; ANOVA). Means with the same letter are not significantly different (p<0.05; Fisher’s LSD test).