MDMA affects the brain by increasing the activity of at least three neurotransmitters (the chemical messengers of brain cells): serotonin,89,90 dopamine, and norepinephrine.91 Like other amphetamines, MDMA enhances release of these neurotransmitters89–92 and/or blocks their reuptake,93,94 resulting in increased neurotransmitter levels within the synaptic cleft (the space between the neurons at a synapse).