Effects of methamphetamine (METH) and SN79 on striatal 5-HT levels. A, dose response effects of METH on 5-HT levels in the striatum. Male, Swiss Webster mice (N = 5–10/group) were injected with METH (1.25–10.0 mg/kg, i.p.) or saline (0 mg/kg, i.p.) at 2 h intervals for a total of four times. Striatal tissue samples were collected one week later and measured for 5-HT concentration. B, effect of SN79 pretreatment on METH-induced alteration of 5-HT levels in the striatum of mouse brain. Male, Swiss Webster mice (N = 5–10/group) were pretreated with saline or SN79 (1, 3, 10 mg/kg, i.p.), and 15 min later, the mice were treated with saline (-METH 0 mg/kg, i.p.) or METH (+METH 10 mg/kg, i.p.). These treatment combinations were repeated at 2 h intervals a total of four times. One week later, mouse striatum were collected and 5-HT concentration was measured. Data was reported as mean ± SEM. **P<0.01 vs. saline, #P<0.05, ##P<0.01, ###P<0.001 vs. METH.