Figure 4.

Effect of ambient temperature on the levels of 5-HT, 5-hydroxytryptophan (5-HTP) and density of [³H]-paroxetine labelled 5-HT uptake sites in cerebral cortex, hippocampus and striatum of rats kept at 22 (open bars) or 4°C (filled bars) for 4 h before and 6 h after MDMA 12.5 mg kg⁻¹, i.p. administration. Animals were killed 7 days after treatment. For the quantification of 5-HTP, rats were treated with NSD-1015 (100 mg kg⁻¹, i.p.) 30 min before killing. Results shown as mean±s.e.m., n=5–7. Different from the corresponding saline group: ^*P<0.05, ^**P<0.01, ^***P<0.001. Different from MDMA-treated animals at 22°C: ^ΔP<0.05, ^ΔΔP<0.01, ^ΔΔΔP<0.001. One-way ANOVA followed by Newman–Keuls test. Levels in saline-treated rats at 22 and 4°C were: for cortex 5-HT (239±9 and 189±17 ng g⁻¹ tissue, respectively), 5-HTP (270±16 and 272±14 ng g⁻¹ tissue, respectively) and 5-HT uptake sites (139±2 and 131±6 fmol mg⁻¹ protein, respectively); for hippocampus 5-HT (332±15 and 411±20 ng g⁻¹ tissue, respectively), 5-HTP (308±19 and 316±10 ng g⁻¹ tissue, respectively) and 5-HT uptake sites (110±8 and 119±9 fmol mg⁻¹ protein, respectively); for striatum 5-HT (388±20 and 464±12 ng g⁻¹ tissue, respectively), 5-HTP (525±34 and 572±31 ng g⁻¹ tissue, respectively) and 5-HT uptake sites (322±25 and 334±7 fmol mg⁻¹ protein, respectively).