Context: Recently, researchers of IIT Dhanbad and CSIR-Indian Institute of Chemical Biology (Kolkata) have developed the Z-scan method to monitor the origin as well as the progression of Parkinson’s disease in human beings.
About Parkinson’s Disease

• It is a progressive disorder that is caused by degeneration of nerve cells in the part of the brain called the substantia nigra, which controls movement.
• These nerve cells die or become impaired, losing the ability to produce an important chemical called dopamine.
• Normally, these neurons produce an important brain chemical known as dopamine. When the neurons die or become impaired, they produce less dopamine, which causes the movement problems of Parkinson's.
• People with Parkinson's also lose the nerve endings that produce norepinephrine, the main chemical messenger of the sympathetic nervous system, which controls many automatic functions of the body, such as heart rate and blood pressure.
• There are currently no blood or laboratory tests to diagnose non-genetic cases of Parkinson's disease.

Symptoms

• Early in the disease, the most obvious symptoms are shaking, rigidity, slowness of movement, and difficulty with walking.
• Thinking and behavioral problems may also occur.
• Dementia becomes common in the advanced stages of the disease.
• The main motor symptoms are collectively called “parkinsonism”, or a “parkinsonian syndrome”.
• Cause: The cause of Parkinson’s disease is unknown, but is believed to involve both genetic and environmental factors.
• Treatment: There is no cure for this disease. The treatment mainly aims to improve the symptoms.

Aggregation of a protein – Alpha-synuclein

• An aggregation of a protein called Alpha-synuclein (ASyn) plays a crucial role in the development of Parkinson’s disease. Protein aggregation is a biological phenomenon in which destabilized proteins aggregate (i.e., accumulate and clump together) leading to many diseases.
• Alpha-synuclein is a protein found in the human brain, while smaller amounts are found in the heart, muscle and other tissues.
• In the brain, alpha-synuclein is found mainly at the tips of neurons in specialized structures called presynaptic terminals.
• Presynaptic terminals release chemical messengers, called neurotransmitters.
• The release of neurotransmitters relays signals between neurons and is critical for normal Brain Function.

Use of Z-scan Method

• The team has found that the Z-scan method is really a technique that could help in monitoring both the early and late stages of the aggregation of ASyn nicely.
• They found that the protein possesses nonlinearity starting from its monomeric state to the fibrillar structure.
• The team is exploring ways to use the Z-scan method to study ASyn aggregates ex vivo (in an external environment) using a suitable animal Parkinson’s disease model.