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Sydney Morning Herald, Australia Wednesday, August 18, 1999 Brain discovery may hold key to disease By JULIE ROBOTHAM, Medical Writer An area in the centre of the brain may be responsible for Parkinson's disease, in addition to the brain stem that is the focus of current drug therapies, Sydney scientists have discovered. Using donated tissue from the "brain bank" at the Prince of Wales Medical Research Institute, neuropathologist Dr Jasmine Henderson and her colleagues have found that a part of brain called the thalamus contains on average 40 per cent less cells in those people who had the disease, compared with those without a brain disorder. The breakthrough, which will be presented to an international conference on Parkinson's disease in Sydney next week, could lead to the development of new drugs because the chemistry of the thalamus is very different from that of the brain stem, Dr Henderson told the Herald yesterday. It could also explain why the present generation of anti-Parkinson's drugs often improved the condition at first while symptoms reappeared later, Dr Henderson added. The thalamus was more usually associated with attention and consciousness than with the impairments to movement that were characteristic of Parkinson's, Dr Henderson said. But the area, which measures about four cubic centimetres, had recently been found to have a role in how the brain instructed the body to move. Parkinson's is characterised by slow, stiff movements. It was only by meticulous counting of the cells of the thalamus that her team was able to identify the deficiency, Dr Henderson said. "If you're doing routine pathology, you ask, 'does this look atrophied or shrunk?', and in this case it doesn't," she said. "We're the only group that's attempted to do this and found this." Although the damage to the thalamus was found in all the brains where Parkinson's had been diagnosed, there was no correlation between the degree of cell loss and the duration or severity of the sufferer's condition. This indicated the degeneration probably began early in the disease's onset, Dr Henderson said, concurrently with the changes to the brain stem, which could be addressed with drugs to change the way the body regulates the brain chemical dopamine. But she warned it would not be easy to create new drugs targeting glutamate, the principal chemical controlling the thalamus. Giving Parkinson's patients extra glutamate could over-stimulate other areas of the brain, Dr Henderson said. This material is subject to copyright and any unauthorised use, copying or mirroring is prohibited. -- Bruce Wallace, brother of Ken 63/3 Sydney, Australia - [log in to unmask]