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. 2013 Feb 27;38(7):1163–1175. doi: 10.1038/npp.2013.35

Figure 1.

Figure 1

The effects of continuous darkness (DD) and photoreceptor ablation (MNU) on forced swimming test (FST)-associated behaviors. (a) Immobile score from the FST in 12-h light:12-h dark (LD) and DD conditions, and after MNU treatment (MNU-LD and MNU-DD). Zeitgeber Time (ZT) 0=light onset in LD; animals in DD tested at ZT of previous LD cycle (mean±SEM, n=6/group/ZT). DD elevated immobile score vs LD at each ZT; MNU reduced immobile score at all ZTs vs LD or DD. Two-way ANOVA, Tukey's post-hoc test; **p<0.001. (b) Immunohistochemically stained retinal sections from untreated (top) and MNU-treated (bottom) animals. DAPI stain (left) illustrating retinal cellular layers: outer nuclear layer: ONL; outer plexiform layer: OPL; inner nuclear layer: INL; inner plexiform layer: IPL; ganglion cell layer: GCL. TUNEL stain (right) illustrating absence of apoptosis in untreated animal (top right) and apoptotic programmed cell death and photoreceptor depletion in the ONL after MNU treatment (bottom right). Bar=20 μm. (c) FST climbing, swimming, and immobility scores at ZT6 for controls and MNU-treated animals. Immobile score values are taken from ZT6 in (a); (n=6/group). DD elevated immobile score and decreased swimming score vs LD; MNU decreased immobile score and elevated swimming score vs DD. Climbing scores did not differ significantly among groups. One-way ANOVA, Tukey's post-hoc test; **p<0.001.