[Ronhutton]

How about this for a theory.
We all know dopamine can't pass the BBB, so in our medication, we take levodopa which can penetrate the BBB, and is converted to dopamine in the brain. In the brain, the dopamine can't leak out, since the famous BBB is keeping it in. This is true for a normal person, but not for us. Prof Leederman has proved we have leaky BBB's. See where I am going? If the BBB is leaky, perhaps after all, we can generate dopamine in our brains, but with a body that is much larger than our brain, and many pints of blood circulating in it, our precious dopamine leaks OUT through our defective BBB, into the body.
Dopamine is natural in the body, where it acts as a hormone, and regulates heartbeat. In an operation, where a patient's heart falters, doctors administer dopamine to get a sluggish heart to beat stronger.
We may not have a deficiency of dopamine neurons, they may work perfectly well, but the bulk of the dopamine we make in our brains may leak out. It puzzled me, that things which widen the BBB, like stress, have such a quick effect on PD symptons.. So, the cause of our sudden deterioration in PD symptons could not be that the more leaky BBB lets in toxins from the bloodstream, and then attacks our dopamine neurons. That must take time,the effect would not be instant on PD symptons. Stress must cause the BBB floodgates to open, and allow the remainder of our dopamine to escape to the body. Don't heartbeats also speed up, as well as PD symptoms go worse, when we encounter stress!!! The influx of toxins as the BBB gets more porous, may be a secondary longer term process aggravating our symptons. We can counter that by taking things which slowly lower the BBB permeability, like curcumin, alpha lipoic acid, GDNF, etc
This leakage may be the major route by which we have a deficiency of dopamine, and restricted movement. PD may be a predominently old person's disease, since the BBB, like the rest of our body, deteriorates slowly, and becomes more leaky. The permaeability of the BBB may then reach a threshold value, when it gets to the stage of just starting to leak dopamine. At that point, we are diagnosed as having PD.
We continue to age, and our small leakage gets ever faster, hence our disease is progressive with time, and PD is an old persons disease. Our meds last less time, as we progress, since increasingly, the dopamine we synthesise from the levodopa starts to flood out as soon as we make it.
We could go on answering questions about PD, such as why have hypertension (high blood pressure) drugs just been found to be of value in PD? See the Isradipine thread. From the above now we can answer that question. High blood pressure also damages the BBB.
There are other questions we could ask ourselves, which may add to the above evidence, (Or they may shoot it down!!!)
The following increase the symptons of PD. Do they widen the pores of the BBB?
Paraquat,
Rotenone,
Maneb (fungicide)
Manganese
MTPT
Toluene
N-hexane
Any help in doing the literature searches gratefully received
Also, any contributions, positive or negative so we can get to the bottom of this.
So the question to research may be, how do we control the permeability of the BBB, rather than look at ways to regenerate brain neurons. If they aint broke, don't fix them!!!