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Supplemental Fig. 3 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

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posted on 19.03.2018 by Melissa Cui Bender, Caroline Hu, Chris Pelletier, Robert J. Denver
Functional leptin signaling in tadpole brain increased during metamorphosis. We investigated changes in functional leptin signaling in the ventral hypothalamus (VH) 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: C – central thalamic nucleus, LH – lateral hypothalamus, Lpv – lateral thalamic nucleus, pars posteroventralis, NPv – nucleus of the paraventricular organ, P – posterior thalamic nucleus, VH – central hypothalamus, VM – ventromedial thalamic nucleus. B. Tadpoles were given i.c.v. injections of 0.6% saline or rxLeptin (20 ng/g*BW) and killed one hr later for IHC for pSTAT3-ir (see Supplemental Methods). Injection of rxLeptin, but not saline caused the appearance of pSTAT3-ir in the regions of the tadpole anterior and posterior VH. The scale bar in the top left image equals 50 m and applies to all photomicrographs in the panels. Labels: aVH – anterior ventral hypothalamus, pVH – posterior ventral hypothalamus, ME – median eminence, Pit – pituitary. C. Changes in mean nuclei count of pSTAT3-ir cells in the anterior and posterior regions of the tadpole VHA 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=3-8/developmental stage). We saw statistically significant changes in pSTAT3-ir during metamorphosis in both regions of the VH (anterior VH: F(4,14)=5.528, P=0.007; posterior VH: F(4,33)=9.442, P<0.0001; ANOVA). Means with the same letter are not significantly different (p<0.05; Fisher’s LSD test).