Figure 2

(A-C) Exercise reduces ERK signaling in the PFC of rats following cocaine reinstatement. Tissue was obtained following the cocaine reinstatement test for 8 of the 11 rats in the exercising group and 7 of the 10 rats in the sedentary group. Total ERK 1 and 2 (A) and pERK 1 and 2 (B) were quantified by densitometry, and the data were normalized to tubulin. Immunoblots for detection of total ERK and pERK are shown above each respective panel. (A) Total ERK levels did not differ significantly between the exercise and sedentary groups (P = 0.08; ERK1, P = 0.91, ERK2). (B) Exercising rats had reduced levels of pERK in the PFC as compared to sedentary rats (ERK1; t₍₁₃₎ = 3.92, P=0.04; ERK2; t₍₁₃₎ = 4.43, P=0.02). (C) The ratio of pERK/total ERK was significantly decreased for ERK2 (t₍₁₃₎ = 4.38, P=0.03) but not for ERK1 (P = 0.23). An asterisk indicates a significant group difference (P < 0.05). (D-E) No effect of exercise on ERK signaling in the PFC among saline control animals. Tissue was obtained following the reinstatement test for 8 of the 8 rats in the exercising group and 7 of the 7 rats in the sedentary group. Total ERK 1 and 2 (C) and pERK 1 and 2 (E) were quantified by densitometry, and the data were normalized to tubulin. Immunoblots for detection of total ERK and pERK are shown above each respective panel. (D) Total ERK levels did not differ significantly between the exercise and sedentary groups (P’s > 0.10). (E) pERK levels did not differ significantly between the exercise and sedentary groups (P’s > 0.10). Error bars represent SEM.