Alzheimer s disease, which initially affects memory formation, is associated with a shortage of acetylcholine. It helps control muscle activity and is an important part of the visual system. Drugs that increase GABA levels in the brain are used to treat epileptic seizures and tremors in patients with Huntington s disease. Serotonin is an inhibitory neurotransmitter that constricts blood vessels and brings on sleep. It is also involved in temperature regulation.
Dopamine is an inhibitory neurotransmitter involved in mood and the control of complex movements.
The loss of dopamine activity in some portions of the brain leads to the muscular rigidity of Parkinson s disease. Many medications used to treat behavioral disorders work by modifying the action of dopamine in the brain. When the brain is healthy it functions quickly and automatically. But when problems occur, the results can be devastating. Some 50 million people in this country one in five suffer from damage to the nervous system.