Background: 3,4- methylenedioxymethamphetamine (MDMA) is a chemical derivative of amphetamine that can induce learning and memory impairment. Due to the effect of neurotrophins on memory and learning, the impact of MDMA was evaluated on the brain - derived neurotrophic factor (BDNF), neurotrophin- 4 (NT-4), and tropomyosin- related kinase B (Trk- β) expression in the hippocampus. Methods: In...