Figure 3. Muscle functionality and behavior in young and old WT, Tg, and Ghrl KO mice. (A) Average score trend in hanging wire test of 3-month old (young) and 24-month old (old) WT, Tg, and Ghrl KO mice and (B) average holding impulse in the same test. Young mice: WT = 21, Tg = 21, Ghrl KO = 27; old mice: WT = 9, Tg = 16, Ghrl KO = 7. *p<0.05 and **p<0.01 vs WT. (C) Memory was evaluated through the object recognition test and expressed as a discrimination index between a familiar and a novel object (seconds on novel – seconds on familiar)/(seconds on novel + seconds on familiar). (D) Anxiety was assessed as the time spent immobile during 6 minutes of tail suspension. Young mice: WT = 5, Tg = 5, Ghrl KO = 6; old mice: WT = 6, Tg = 7, Ghrl KO = 6. For each box plot, the lower and up boundaries denote the 25th and the 75th percentile of each data set, respectively, the horizontal line represents the median, and the whiskers represent the min and max of values. *p<0.05 and **p<0.01 old vs. young; $p<0.05 and $$p<0.01 Tg and Ghrl KO vs. WT.