Effect of pretreament with low dose MDMA (3 mg/kg, i.p.) on MDMA (12.5 mg/kg, i.p.)-induced neurotoxicity in frontal cortex 7 days later. (A) Pretreatment with four consecutive doses of low dose MDMA attenuated the loss of 5-HT transporters induced by neurotoxic MDMA given 24 h later. (B) Pretreatment with a single low dose of MDMA attenuated the loss of 5-HT transporters induced by neurotoxic MDMA given 24 h, 96 h or 168 h (7 days) later. (C) Pretreatment with low dose MDMA 96 h earlier did not modify neurotoxic MDMA-induced hyperthermia. The arrow marks the time of neurotoxic MDMA injection. Results shown as mean ± s.e.mean, n = 5-8. Different from saline-treated controls: *P < 0.05, **P < 0.001. Different from neurotoxic MDMA: ΔP < 0.05, ΔΔP < 0.01. One-way ANOVA followed by Newman-Keuls test.