Figure 1.

Acute effect of ghrelin (0, 0.3, and 3.0mg/kg, i.p.) on anxiety- and depression-like behavior in male NMRI mice. (a-c) Ghrelin increased center entries (a), center time (b), and distance moved (c) in the open field arena at both doses tested, indicating an anxiolytic-like effect of ghrelin (n=8). (d-f) Ghrelin dose-dependently increased open arm entries (d) and time (e) in the plus maze test, reaching statistical significance with the highest dose on open arm entries, while having no effect on total entries (f), supporting an anxiolytic-like effect of ghrelin (n=17–18). Open arm entries and time were calculated as open arm/(open+closed arms). (g-h) Ghrelin had no effect on time spent immobile (g) or latency to the first immobility (h) in the forced swim test (n=10). (i) Ghrelin had no effect on time spent immobile in the tail suspension test (n=10). Asterisks indicate statistical significance compared with the vehicle group in a Dunnett’s posthoc test after significant 1-way ANOVA (*P<.05, **P<.01).