The correct answer is serotonin and oxytocin.
MDMA (amphetamine) enhances the release of serotonin, and/or blocks its reuptake. As a result neurotransmitter levels within the synaptic cleft are increased. Because serotonin regulates the mood, sleep, pain, its elevated levels causes the mood-elevating effects people experience.
Elevated levels of oxytocin ("the love hormone" ) increase trust, promote social bonding, and foster compassion.