Breakthrough Research for Parkinson’s Disease Drugs
November 19, 2009
Australian scientists have significantly advanced the understanding of dopamine release from nerve cells, findings that should speed the development of more effective drugs for treating Parkinson's Disease, Which results in muscle rigidity, tremor, a slowing of physical movement and, in extreme cases, a loss of physical movement. These primary symptoms are caused by the loss of dopamine producing nerve cells in the brain. Medicines used for treating Parkinson's either provide extra dopamine or attach to the remaining nerve cells that release dopamine and regulate its release. In the latter case, no one understands the mechanisms involved, or how to control them. To address this, neuroscientists at Sydney's Garvan Institute of Medical Research have developed a mathematical model and microscopy method that reveal the mechanisms behind synaptic dopamine release and the factors that govern the probability of release. These findings made by Drs. James Daniel and Bryce Vissel have been published online in the Journal of Neuroscience. "While there has been an enormous amount of effort put into the development of drugs for Parkinson's disease, very little has been known about how the dopamine releasing drugs achieve their effects, other than the fact they attach to a receptor on a dopamine nerve cell, and then something happens," said Dr. Vissel. According to Vissel, we are still in the dark ages in understanding the sub-microscopic events that take place in the brain. "We have roughly 100 billion nerve cells in our brains, with up to 100,000 connections each. We're only just beginning to understand that every connection is regulated in the most extraordinarily sophisticated way," he explained. "The surprising thing is that out of all this irregularity and complexity comes predictable or reliable function. Most of us can catch a ball that is thrown to us without dropping it, for example. When you think about the millions of nerve cell events in that simple act alone, it's remarkable. Unfortunately, in Parkinson's disease this phenomenal ability to regulate movement is lost. Our work helps de-mystify the part of the process that takes place at the dopamine nerve cell synapse. We believe it will help us work out how drugs currently being used to treat Parkinson's disease are regulating dopamine release. It will also open up new avenues for pharmaceutical development."