Speed alters these normal conditions in three ways:
Speed (amphetamine) arrives in the brain via the blood. It penetrates into dopamine or noradrenaline neurons with the aid of reuptake proteins. In the axon terminal, speed causes the neurotransmitter vesicles to release all of their noradrenaline or dopamine. These transmitters then move across the synapse to the receptors on the next cell, relaying the signal further.