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Jacob, In idiopathic PD the cells in the substantia nigra die. l-dopa works because it provides extra precursor (raw material) for the production in the remaining cells of dopamine therefore increasing the amount of dopamine in the synapse (which I believe is in the putamen). This function is considered to be presynaptic. In PD the postsynaptic receptors are intact. They are essentially waiting there starved for dopamine needing that (or an agonist which mimics the action of dopamine) to fire. The increased presynaptic dopamine provided by the stimulated presynaptic neurons returns function to more or less normal. Transplant is of dopamine producing presynaptic neurons usually placed directly in the putamen where normally their axons project. If the postsynaptic receptors are damaged and they are not dopamine responsive then a procedure like fetal cell transplant which increases dopamine theoretically would do nothing. I remember seeing a web site which explained the basic neurophysiology with animated diagrams. I will try to find that site and post it for everyone. Charlie Jacob Drollinger wrote: > > Dear friends, > > I am not currently taking sinemet. However the reason I am not taking the > "Traditional" P.D. med is not because of my youth, but because I have been > led to believe that I would be non-responsive to it. > Having incurred only post-synaptic damage to the globus pallidus, I had been > told that more dopamine would make no change in my symptoms. > Now, I have been informed by Carole H. that their program for fetal tissue > implants requires a positive response to sinemet. > Could someone please try to explain to me the physiology of Dopamine? By that > I mean, would sinemet help provide dopamine to the basal ganglia? > > Jacob -- CHARLES T. MEYER, M.D. Middleton, WI [log in to unmask]