Parkinson's Disease

Parkinson’s disease, also known as hypokinetic rigid syndrome (HRS), is an idiopathic and has no known cause. It is normally due to the degeneration of dopaminergic neurones of the nigrostriatal tract and loss of dopamine (DA) neurotransmission in the striatum. The symptoms of this disease are a resting tremor, muscle rigidity and suppression of voluntary movements (hypokinesis). In the later stages, mental and behavioural problems may occur such as depression and even dementia.

The main 4 dopaminergic pathways are:-

1. Nigrostriatal - Substantia nigra to striatum
2. Striatum Mesolimbic - Ventral tegmental area to nucleus accumbens
3. Mesocortical - Ventral tegmental area to frontal cortex
4. Frontal cortex Tuberoinfundibular - Arcuate nucleus to pituitary gland

The decarboxylase inhibitor – carbidopa, the MAO inhibitor: Selegiline and D2 receptor agonists like Bromocriptine can be used to treat Parkinson’s disease.