Answer & Explanation:
Whether dopamine is excitatory or inhibitory depends on the type of effect on the target neuron, on the type of receptor on the surface of the neuron membrane, and on how the neuron responds to an increase or decrease in concentration of cAMP levels in specific. Studies have shown that symptoms of Parkinson's disease develop in patients with an 80% or more loss of dopamine-producing cells in the basal region. Normally, dopamine works in a delicate balance with other neurotransmitters to help coordinate the millions of nerve and muscle cells involved in movement. People with Parkinson's disease have involuntary or uncontrolled movements, such as tremors, stiffness, and difficulty with balance and coordination that are thought to be caused by a lack of dopamine balance.