Fig. 3.
Effects of intrathecal (i.t.) pretreatment of 5,7-dihydroxytryptamine (DHT) creatinine sulfate (100 μg), a selective neurotoxin for serotonergic terminals, on intraperitoneal (i.p.) morphine (MOR)-induced analgesia (10 mg/kg) in normal (A) and spinal nerve ligation (SNL) rats (B). Time-course effects (A, B) and area under the time-course curve (AUC) (C) are shown. Withdrawal thresholds are expressed as the mean ± SD for six rats in each group. *P < 0.05 compared with saline (SAL) plus morphine-treated group at each time point (two-way repeated-measures ANOVA followed by Student–Newman–Keuls post hoc tests). #P < 0.05 compared with the saline plus morphine-treated group (one-way ANOVA followed by Student–Newman–Keuls post hoc tests).