Box plot of jumps and immobility time in dependent mice without precipitation (grey, n = 14), in dependent mice with precipitation (red, n = 13) and in non-dependent mice with naloxone injection (white, n = 13; jump Kruskal–Wallis test: H (3) = 26.79, P < 0.001; immobility time Kruskal–Wallis test H (3) = 28.94, P < 0.001; Dunn’s multiple comparisons test, ** P < 0.01, *** P < 0.001). F, fentanyl; N, naloxone; S, saline.
