ABSTRACT
In Parkinsonism, all of the functions are progressively impaired; there is coarse tremor at rest and excessive muscle tone, movements are slow to start and slower to stop and co-ordination with other muscle groups is poor. In its later stages Parkinsonism, much more widespread and unpleasant symptoms indicate that the neurological damage includes much more than the motor control centres. These include psychiatric symptoms - depression, anxiety, dementia, apathy and sleep disturbance. Dopamine is supplied as the 'pro-drug' levodopa, which is metabolised to dopamine in the brain, where it relieves the symptoms of Parkinsonism effectively, in the early stages. The drug industry has overcome this problem by combining levodopa with either of two other drugs which inhibit the peripheral breakdown of dopamine and ensure that a sufficient amount reaches the central nervous system. A further group of drugs, the anticholinergics, block the excessive excitatory action of the cholinergic neurons in the corpus striatum.
