Background to Parkinson's Disease Background of Parkinson's Disease Normal Brain Function Pathology of Parkinson's Disease Symptoms Demographics Normal Brain Function Nerve cells use a variety of chemical messengers called neurotransmitters to communicate with each other. Neurotransmitters serve to carry messages between nerve cells by crossing the synapse, or space between nerve cells.
Neurotransmitters also allow nerves to communicate with muscle cells in order to create motion.
One especially important messenger is dopamine. Dopamine is manufactured in the substantia nigra. When a message needs to be sent from one nerve cell to another, packets of dopamine are released into the synapse. The dopamine particles in these packets flow across the synapse and fit into receptors on the outside of the receiving nerve cell. The receiving cell is now stimulated to send on the message, so it gathers its own packets of dopamine and passes along the message to the next nerve cell in the same way.