Figure 4. Alterations in spine morphology of rat NAc MSNs 21d after morphine or cocaine administration.

All experiments below were performed in rats 21d after the 5d drug procedure. a Example images of dendrites in NAcSh slices from saline (n=16 rats)-, cocaine (n=18 rats)-, or morphine (n=17 rats)-exposed rats with or without co-administration of peptides. b Summary showing that total spine density was increased in cocaine-exposed rats but decreased in morphine-exposed rats. Co-administration of GluA2_3Y selectively prevented morphine-induced decreases in total spines with no effect on cocaine-induced increase in total spines (F_2,42=100.4, p=0.00, two-way ANOVA with Bonferroni posttest). c Summary showing that density of filopodia-like spines was increased in cocaine-exposed rats, and this increased was not affected by co-administration of GluA2 peptides (F_2,42=25.96, p=0.00, two-way ANOVA with Bonferroni posttest). d Summary showing that density of mushroom-like spines was increased in cocaine-exposed rats, and this increase was not affected by co-administration of GluA2 peptides (F_2,42=41.16, p=0.00, two-way ANOVA with Bonferroni posttest). e Summary showing that density of long-thin spines was increased in cocaine-exposed rats, but decreased in morphine-exposed rats, and these effects were prevented by co-administration of GluA2_3Y (F_2,42=32.56, p=0.00, two-way ANOVA with Bonferroni posttest). f Summary showing that density of stubby spines in cocaine- or morphine-exposed rats (F_2,42=6.94, p=0.00, two-way ANOVA). Error bar=s.e.m., *p<0.05, and **p<0.01.