Fig. 2
Electrophysiological, biochemical, and morphological assays associated with excitability changes in striatal MSNs. a Example confocal images of MSNs in the NAcS of rats 21 days after withdrawal from CIW or CIE treatment during adolescent or adult stage. b Example DIC image at a high magnification (through ×40 objective) showing an MSN in the NAcS patched with a micropipette. c–j Decreased mAHP in NAc MSNs from rats exposed to CIE during their adolescent stage. Example traces showing the fAHP and mAHP in NAcS MSNs from rats treated with CIW vs. CIE during their adolescent (c) and adult (d) stage. Summarized data showing that the mAHP (e, Ado/Adu × CIW/CIE interaction, F1,62 = 9.2, p < 0.01, cell based; F1,28 = 6.5, p = 0.02, animal based), but not fAHP (h, Ado/Adu × CIW/CIE interaction, F1,62 = 1.6, p = 0.21, cell based; F1,28 = 0.9, p = 0.35, animal based), was decreased in NAcS MSNs in rats pretreated with CIE during their adolescent stage relative to those treated with CIW during their adolescent stage or those treated with CIW or CIE during their adult stage. In NAcC MSNs in rats pretreated with CIE, either during their adolescent or adult stage, compared with those treated with CIW, mAHP was decreased (f, Ado/Adu × CIW/CIE interaction, F1,35 = 0.2, p = 0.65, cell based; F1,13 = 0.1, p = 0.73, animal based; Ado/Adu, F1,35 = 0.2, p = 0.67, cell based; F1,13 = 0.2, p = 0.67, animal based; CIW/CIE, F1,35 = 23.4, p < 0.01, cell based; F1,13 = 14.9, p < 0.01, animal based), but not fAHP (i, Ado/Adu × CIW/CIE interaction, F1,35 = 0.6, p = 0.44, cell based; F1,13 = 0.3, p = 0.62, animal based). Neither the amplitude of fAHP (j, Ado/Adu × CIW/CIE interaction, F1,56 = 0.6, p = 0.45, cell based; F1,17 = 0.8, p = 0.38, animal based) nor mAHP (g, Ado/Adu × CIW/CIE interaction, F1,56 = 0.9, p = 0.36, cell based; F1,17 = 1.0, p = 0.33, animal based) in DLS MSNs was affected in rats pretreated with CIE during their adolescent stage. k–p Decreased SK3 protein expression in the NAcS from rats exposed to CIE during their adolescent stage. Example western blotting bands showing SK3 protein levels in the NAcS (k), NAcC (l), and DLS (m) from rats treated by CIW vs. CIE during their adolescent and adult stage, respectively. Summarized results showing that decreased SK3 protein level in the NAcS from rats exposed to CIE during their adolescent but not adult stage (n, Ado/Adu × CIW/CIE interaction F1,20 = 30.1, p < 0.01) and the NAcC from rats exposed to CIE during both their adolescent and adult stage (o, Ado/Adu × CIW/CIE interaction F1,12 = 0.26, p = 0.61; CIW/CIE F1,12 = 5.0, p = 0.04; Ado/Adu F1,12 = 0.01, p = 0.92), but not in the DLS from rats with either adolescent or adult CIE history (p, Ado/Adu × CIW/CIE interaction F1,20 = 0.3, p = 0.61). q–s Morphological changes in NAcS MSNs. Summarized data showing the somatic area (q, Ado/Adu × CIW/CIE interaction, F1,18 = 0.1, p = 0.98, cell based) and the number of primary (r, Ado/Adu, F1,18 = 11.6, p < 0.01, cell based; CIW/CIE, F1,18 = 5.7, p = 0.03, cell based; interaction, F1,18 = 1.6, p = 0.22, cell based) and secondary dendrites (s, Ado/Adu × CIW/CIE interaction, F1,16 = 0.1, p = 0.99, cell based) per MSNs in the NAcS from rats with a history of CIW/CIE during adolescent or adult stage. The cell number/animal number (i.e., m/n in c–j, q–s) or the animal number (i.e., n in n–p) is shown in parentheses for each group. Data were analyzed by two-way ANOVA, followed by Bonferroni post test. *p < 0.05; **p < 0.01
