In obese (ob/ob) mice, eating behavior is higher and they rest less, and these mice don’t respond strongly to ghrelin or a ghrelin blocker. In normal mice, the blocker (D‑Lys‑GHRP‑6) caused a big drop in food intake and some nasty side effects, messing up normal feeding patterns.

Behavioral satiety sequence (BSS) is a useful paradigm to assess the effects of orexigenic and anorexigenic profiles of novel pharmacological and genetic manipulations in rodents. To date, no studies have described the satiety profile of leptin-deficient ob/ob mice, an important animal model of obesity in this task. Furthermore, no studies have described changes in the BSS after treatment with ghrelin receptor ligands, which have become an attractive therapeutic target in obesity drug discovery efforts. BSS testing was carried out in ob/ob mice and their lean controls. After baseline analysis, effects of ghrelin (2 nmol/10 g) and of the ghrelin receptor antagonist (D-Lys)-GHRP-6 (66.6 and 133.3 nmol/10 g) were studied in BSS in mice of both genotypes. The baseline BSS profile of ob/ob mice showed an increased eating and a decreased resting activity. Ob/ob mice presented with a decreased sensitivity to the stimulation with ghrelin and with the ghrelin receptor antagonist, which caused strong anorexic and adverse side effects in lean mice, thereby disrupting the BSS profile. BSS is an indispensable tool for parsing the role of the ghrelinergic system in satiety, to characterize transgenic mice and to elicit behavioral feeding profiles of novel anorectic agents.