Dual effects of 3,4-methylenedioxymethamphetamine (ecstasy) on survival and apoptosis of primary hippocampal neurons

BACKGROUND: 3, 4-methylenedioxymethamphetamine (MDMA, also known as "ecstasy") hasbeen shown to exhibit neurotoxic effects on the hippocampus. However, exposure to sub-lethalinsults of MDMA has been reported to result in neuroprotection.OBJECTIVE: To investigate the effects of MDMA on hippocampal neuronal viability, caspase-3activity, and mRNA expression of the N-methyl-D-aspartate (NMDA) receptor 2B (NR2B) subunit.DESIGN, TIME AND SETTING: A cytological, in vitro experiment was performed at the Departmentof Anatomy, School of Medicine, and Department of Toxicology-Pharmacology, Faculty of PharmacyTehran University of Medical Sciences in 2008.MATERIALS: MDMA was extracted from ecstasy tablets, which were kindly supplied by thePharmacology-Toxicology Department, Faculty of Pharmacy, Tehran University of Medical Sciences, Iran.METHODS: Hippocampal neurons were isolated from Wistar rats at gestational day 18. Followingprimary culture, hippocampal neuronal viability was detected by MTT assay. Varying concentrationsof MDMA (100 5 000 μmol/L) were used to determine lethal concentration 50 (LC50), which wasaround 1 500 μmol/L. Five concentrations of MDMA below 1 500 μmol/L (100, 200, 400, 800, and1 050 μmol/L) were used for the remaining experiments. After 24 hours of MDMA treatment,NR2B mRNA expression was detected by RT-PCR, and caspase-3 relative activity was determinedby colorimetric assay.MAIN OUTCOME MEASURES: Hippocampal neuronal viability, caspase-3 activity, andNR2B mRNA expression.RESULTS: MDMA-induced neurotoxicity in hippocampal neuronal cultures was dose-dependent. Inhigh concentrations (1 000-5 000 μmol/L) of MDMA, neuronal viability was decreased. However,with a 500 μmol/L dose of MDMA, neuronal viability was significantly increased (P < 0.01). Lowconcentrations of MDMA (200 and 400 μmol/L) significantly decreased caspase-3 activity (P < 0.01),whereas high concentrations of MDMA significantly increased caspase-3 activity (P < 0.01). NR2Bsubunit mRNA expression was not significantly altered after 100 1 050 μmol/L MDMA exposure.CONCLUSION: MDMA exhibits dual effects on hippocampal neuronal viability and caspase-3activitv. These effects are independent from NR2B subunit expression levels.