The neurotransmitter dopamine is primarily known as the happiness hormone that controls our motivation in the brain’s reward system. However, the neurotransmitter also acts as lubricating oil for our fine motor skills and regulates the movements of our muscles. If dopamine-producing nerve cells die off, affected people experience movement disorders such as tremors or muscle stiffness. The diagnosis: Parkinson’s disease. Researchers suspect that the reason for the death of nerve cells is excessive iron concentrations in the brain.
A team of researchers from Germany and the UK has now developed a method that can be used to determine the iron concentration in the affected regions. With the participation of DESY researchers Gerald Falkenberg and Dennis Brückner, the team led by Evgeniya Kirilina from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, was able to determine possible toxic iron concentrations from MRI (magnetic resonance imaging) measurements of cells using DESY’s brilliant X-ray light source PETRA III. The work could contribute to the development of early diagnoses for Parkinson’s disease.
Parkinson’s disease is one of the most common diseases of the nervous system, affecting around 200,000 people in Germany alone. There is currently no cure for the disease. The typical Parkinson’s symptoms are caused by damaged nerve cells in the substantia nigra, an area in the brain stem. Damaged or dead nerve cells no longer produce enough dopamine or any dopamine at all – the lack of dopamine disrupts signal transmission between the nerve cells.
Iron is required for dopamine production in the nerve cells, and the corresponding nerve cells in the substantia nigra are therefore susceptible to both iron deficiency and excessive amounts of iron. Too much intracellular iron can be toxic, leading to the degeneration and death of neurons in the substantia nigra. “Oxidative stress caused by iron is considered a possible cause of the death of dopamine-producing nerve cells,” says DESY researcher Gerald Falkenberg, head of beamline P06 at DESY’s research X-ray source PETRA III. “That is why we have been looking for methods to measure the amount and distribution of iron in the brain over the course of a person’s life.” According to Falkenberg, this should also be possible for patients in hospitals in the future.
Read more on DESY website
Image: Iron deposits (red) in brain tissue: Using X-ray fluorescence measurements at DESY’s X-ray light source PETRA III, researchers were able to map the iron concentrations in nerve cells of the substantia nigra (region in the brain stem). The cell bodies (yellow) of the dopamine-producing nerve cells have a very high iron concentration.
Credit: E. Kirilina, Department of Neurophysics, MPI for Human Cognitive and Brain Sciences, Leipzig, Germany