Figure 3.

Upregulation of OA-sensitive PPs in the brains of mice receiving repeated administration of cocaine (COC; 10 mg kg⁻¹). Photographs are representative immunoblots of PP1γ, PP2A and PP5 protein in the NAc. Twelve animals went through locomotor testing using the method described for Figure 2. Saline (SAL) or COC was administered to six animals as described in Figure 2. All the animals subjected to the cocaine regimen developed behavioral sensitization. Mice did not go through drug challenge and locomotor testing on withdrawal day 7 before tissue collection. The NAc and the VTA were both isolated from all animals on day 7 of withdrawal. The individual prepared extracts were used in immunoblots using antibody against all examined subtypes of PPs. Student,s t-test revealed that PP2A content in the COC-treated group was significantly different in the NAc (df=10, t=4.69, P=8.61 × 10⁻⁴) and the VTA (df=10, t=8.65, P=5.92 × 10⁻⁶) compared to those given SAL, whereas PP5 content in the COC-treated group was significantly different only in the NAc (df=10, t=9.58, P=2.36 × 10⁻⁶) compared to mice given SAL. n=6. ^***P<0.001 vs SAL, determined by Student's t-test.