The gravitostat protects diet-induced obese rats against fat accumulation and weight gain.

The gravitostat is a novel homeostatic body weight-regulating mechanism, mostly studied in mice, and recently confirmed in obese humans. In the present study, we explored the effect of weight loading on metabolic outcomes, meal patterns and parameters linked to energy expenditure in both obese and lean rats. Diet-induced obese (DIO) and lean rats were implanted with capsules weighing either 15% of biological body weight (load) or empty capsules (1.

Rewarding behavior with a sweet food strengthens its valuation.

Sweet foods are commonly used as rewards for desirable behavior, specifically among children. This study examines whether such practice may contribute to reinforce the valuation of these foods. Two experiments were conducted, one with children, the other with rats.

Functional and Neurochemical Identification of Ghrelin Receptor (GHSR)-Expressing Cells of the Lateral Parabrachial Nucleus in Mice.

The lateral parabrachial nucleus (lPBN), located in the pons, is a well-recognized anorexigenic center harboring, amongst others, the calcitonin gene-related peptide (CGRP)-expressing neurons that play a key role. The receptor for the orexigenic hormone ghrelin (the growth hormone secretagogue receptor, GHSR) is also abundantly expressed in the lPBN and ghrelin delivery to this site has recently been shown to increase food intake and alter food choice. Here we sought to explore whether GHSR-expressing cells in the lPBN (GHSR cells) contribute to feeding control, food choice and body weight gain in mice offered an obesogenic diet, involving studies in which GHSR cells were silenced.

Ghrelin Receptor Stimulation of the Lateral Parabrachial Nucleus in Rats Increases Food Intake but not Food Motivation.

Objective: The lateral parabrachial nucleus (lPBN) in the brainstem has emerged as a key area involved in feeding control that is targeted by several circulating anorexigenic hormones. Here, the objective was to determine whether the lPBN is also a relevant site for the orexigenic hormone ghrelin, inspired by studies in mice and rats showing that there is an abundance of ghrelin receptors in this area.

Methods: This study first explored whether iPBN cells respond to ghrelin involving Fos mapping and electrophysiological studies in rats.

Activation of the rat hypothalamic supramammillary nucleus by food anticipation, food restriction or ghrelin administration.

The circulating orexigenic hormone ghrelin targets many brain areas involved in feeding control and signals via a dedicated receptor, the growth hormone secretagogue receptor 1A. One unexplored target area for ghrelin is the supramammillary nucleus (SuM), a hypothalamic area involved in motivation and reinforcement and also recently linked to metabolic control. Given that ghrelin binds to the SuM, we explored whether SuM cells respond to ghrelin and/or are activated when endogenous ghrelin levels are elevated.