Fig. 4.

The increase in pNR1 is still present after 2 months of withdrawal and is correlated with reward-seeking behavior and decreased levels of calcineurin. (A) Increased levels of pNR1 are observed in withdrawn rats (N = 32) after a 2-month withdrawal period compared with saline controls (N = 8) [t test, t(38) = 3.531, P = 0.0011]. (B) Calcineurin levels were significantly decreased in rats after a 2-month withdrawal period [t test, t(38) = 2.216, P = 0.0327]. (C) The level of pNR1/NR1 significantly correlated with the motivation for a palatable food reward on an operant facial assay at a nonaversive 37°C temperature [Pearson’s correlation: r(38) = 0.3688, R² = 0.1360, P = 0.0449]. (D and E) No correlations were observed at aversive temperatures of 46°C [Pearson’s correlation: r(32) = −0.2698, R² = 0.07280, P = 0.1353] or at 50°C [Pearson’s correlation: r(32) = 0.1641, R² = 0.02692, P = 0.3695]. For all graphs, *P < 0.05 and **P < 0.01, Bonferroni’s post hoc test.