Figure 1.
Schematic diagrams showing the areas in which Fos expression was quantified.
The diagrams adapted from the atlas of Paxinos and Watson (1998) indicate the placement of grids for counting Fos-expressing cells. Bregma 3.2: VO, ventral orbital cortex; Bregma 2.7: Cg, cingulate cortex; dPrL, dorsal prelimbic cortex; vPrL, ventral prelimbic cortex; cortex; IL, infralimbic cortex; Pir, piriform cortex; Acb, accumbens nucleus; Bregma −0.26: LSV, ventral part of the lateral septal nucleus; vBNST, anteroventral part of the bed nucleus of the stria terminalis; Bregma −1.88: PVA, paraventricular thalamic nucleus; PVNp, parvocellular part of the paraventricular hypothalamic nucleus; AH, anterior hypothalamic area; LH, lateral hypothalamic area; Bregma −2.8: DM, dorsomedial hypothalamic nucleus, VM, ventromedial hypothalamic nucleus; CeM, central nucleus of the amygdala; BLA, anterior part of basolateral amygdala; MeA, medial nucleus of the amygdala; Bregma −5.6: V1M, primary visual cortex; S, subiculum; Bregma −7.8: VLPAG: ventrolateral part of the periaqueductal gray.
Figure 2.
Effects of cocaine withdrawal on anxiety-related behavior.
Behavior was assessed in the elevated plus-maze (A–C, n = 7–10), open arm (D–F, n = 10–14) and shock-probe burying tests (G–I, n = 10–14) in cocaine-treated rats (black bars) compared to saline-treated rats (white bars). Data are expressed as mean + SEM. *p<0.05, **p<0.01 versus saline-treated rats and #p<0.05 versus cocaine-treated rats at withdrawal day 2; Kruskal-Wallis test followed by a Mann-Whitney U test for pairwise comparisons.
Figure 3.
Effects of cocaine withdrawal on depression-related behavior.
Behavior was assessed in the sucrose preference (A, n = 5−6) and forced swim tests (B, n = 8−7) in cocaine-treated rats (black circles or black bars) compared to saline-treated rats (white circles or white bars). (A) Evaluation of the preference for 0.5% sucrose solution during 28 days of withdrawal. The small graph on the bottom right shows the measurement of a preference for the sucrose solution at different concentrations in naive rats. The sucrose consumption data were analyzed by a two-way ANOVA with one between-subject factor (treatment) and one within-subject factor (time). (B) Measurement of different behavioral parameters in the forced swim test performed at 2 days of cocaine withdrawal. Data are expressed as mean + SEM. **p<0.01, ***p<0.001 versus saline-treated rats; Kruskal-Wallis test followed by a Mann-Whitney U test for pairwise comparisons.
Figure 4.
Effect of a 2-day cocaine withdrawal on Fos expression in cortical regions after open arm exposure.
Cocaine-treated rats (black bars) were compared to saline-treated rats (white bars) under basal conditions (n = 5–6) and after a 5-min exposure to the open arm test (n = 7–12). Data are expressed as mean + SEM. *p<0.05, **p<0.01 versus the corresponding group of rats in basal conditions, #p<0.05 versus saline-treated rats placed in the open arm; Kruskal-Wallis test followed by a Mann-Whitney U test for pairwise comparisons.
Figure 5.
Effect of a 2-day cocaine withdrawal on Fos expression in subcortical regions after open arm exposure.
Cocaine-treated rats (black bars) compared to saline-treated rats (white bars) under basal conditions (n = 5–6) and after a 5-min exposure to the open arm test (n = 7–12). Data are expressed as mean + SEM. *p<0.05, **p<0.01 versus the corresponding group of rats in basal conditions, #p<0.05 versus saline-treated rats placed in the open arm; Kruskal-Wallis test followed by a Mann-Whitney U test for pairwise comparisons.
Figure 6.
Photomicrographs showing double labeled cells in the cingulate cortex.
Fos-GAD mRNA and Fos-vGlut1 mRNA expressing cells after exposure to the open arm are illustrated on photomicrographs A and B respectively. Arrows point to double labeled cells. In C is illustrated the distribution of GFAP-expressing cells (in black) and NeuN-expressing-cells (in brown). Scale bar = 20 µm.
Table 1.
Densities of neurons and astroglial cells and proportion of Fos-positive cells expressing GAD mRNA or vGlut1 mRNA in the mPFC.