PEOPLE suffering from Parkinson鈥檚 disease have more missing brain cells than anyone suspected. This could change the way the disease is studied and treated, says the Australian team who discovered the deficit.
The missing cells are pyramidal cells, intermediaries that help direct muscles to perform intricate tasks such as writing and doing up buttons. In healthy people these cells get switched on by dopamine released in the back of the brain. But in people with Parkinson鈥檚, this dopamine supply dries up. In an effort to get the pyramidal cells working again, researchers have focused on developing drugs to boost production of dopamine.
But Glenda Halliday of the Prince of Wales Medical Research Institute in Sydney says this approach does not work the way it is intended because the pyramidal cells are simply not there. She believes the limited benefits the drugs do have come from stimulating other as-yet unidentified cells in the cortex to mimic the function of the missing pyramidal cells.
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Halliday and her colleague Virginia MacDonald compared healthy brain tissue with brain tissue taken from people with Parkinson鈥檚 at post-mortem. They found that Parkinson鈥檚 patients have little more than half the normal number of pyramidal cells in the cortex.
This discovery won鈥檛 mean an imminent cure for Parkinson鈥檚. 鈥淏ut it raises the question as to why and how these cells are lost and will stimulate further research,鈥� says neurologist Malcolm Horne of Monash University in Melbourne. This could focus on finding replacements for the missing cells rather than trying to stimulate cells that aren鈥檛 there. It may also shift researchers鈥� attention towards the more mysterious cortex, says Halliday.