A77636 hydrochloride

The following primary antibodies were used throughout this study: rat anti-mouse CD11b (1:400, Abcam), rabbit anti-F-actin (1:1000, Abcam), rabbit anti-COX-2 (1:1000, Abcam), rabbit anti-IL-1β (1:200, Abcam), rabbit anti-GFAP (1:5000, Neuromics), rabbit anti-Iba-1 (1:1000, Wako), goat anti-Iba-1 (1:500, Wako), rabbit anti-AKT (1:1000, Santa Cruz), rabbit anti-p-AKT (Ser473, Thr308) (1:1000, Cell Signaling), rabbit anti-ERK (1:1000, Santa Cruz), rabbit anti-p-ERK (Thr42/44) (1:1000, Cell Signaling), rabbit anti-STAT3 (1:1000, Cell Signaling), rabbit anti-p-STAT3 (Ser727, Abcam), mouse anti-PCNA (1:1000, Santa Cruz), rabbit anti-D2R (1:1000, Abcam), and rabbit anti-D1R (1:1000, Millipore) antibodies. We used the following small molecules: D1R antagonists (LE300, 10 μM, Sigma-Aldrich; SCH23390, 30 μM, Tocris), D1R agonist (A77636 hydrochloride, 10 nM, Tocris), D2R antagonist (eticlopride hydrochloride, 100 nM, Sigma-Aldrich), a STAT3 inhibitor (S3I-201, 50 μM, Sigma-Aldrich), and an ERK inhibitor (PD98059, 10 μM, Millipore).

(−)-Nicotine hydrogen tartrate (Sigma-Aldrich), SCH 23390 hydrochloride (Tocris bioscience), and A77636 hydrochloride (Tocris bioscience) were dissolved in sterile saline (0.9% sodium chloride). SCH 23390 and A77636 were administered subcutaneously (SC) in a volume of 1 ml/kg body weight. Nicotine was dissolved in sterile saline, and the rats self-administered 0.03 or 0.06 mg/kg/inf of nicotine in a volume of 0.1 ml/inf. Nicotine doses are expressed as base, and SCH 23390 and A77636 doses are expressed as salt. The treatment schedule was the same in experiments 1–3. Both SCH 23390 and A77636 were administered (SC) 15 min before nicotine self-administration, food responding, or the small open field test. It was also determined if SCH 23390 affected nicotine and food intake and locomotor activity 24 h after treatment and if A77636 affected these parameters 24 and 48 h after treatment. The doses of SCH 23390 and A77636 were based on previous studies in rats^{18 (link),61 (link)}. SCH 23390 (0, 0.003, 0.01, and 0.03 mg/kg), and A77636 (0, 0.1, and 0.3 mg/kg) were administered according to a Latin square design. The highest dose of A77636, 1 mg/kg, was not included in the Latin square design and was administered last. There was at least 48 h between injections with SCH 23390 and 72 h between injections with A77636^{61 (link)}.