A neuron is a little bit like a chemical plant. It produces dopamine in a number of steps. The diagram above describes the different steps in dopaminesynthesis. The terms in italics are the enzymes which catalyze thesereactions. The dopamine that is produced in this process is not alwaysused immediately.
Dopamine is stored in special storage containers calledvesicles located within the synaptic buttons.
When an electrical impulse that has travelled downa nerve cell's axon reaches the synaptic button, dopamine stored withinsome vesicles is released into the synaptic gap. This interaction triggers an elctricalsignal which will continue to be relayed until the signal reaches its destinationinanother region of the brain. The electrical impulse might initiate an activitysuch as the contraction of a muscle. Not all of the dopamine released into the synaptic gap reachesthe receptor. The amount of free floating dopamine is controlled by a numberof complex chemical reactions.