Hi Paula,
From memory of what I have read, acetylcholine is a chemical messenger which must be in balance with dopamine. The reason for this is one tensions muscles and the other relaxes them, for normal movement. I have seen it described as one "pushes and the other pulls".
Dopamine enables movement and acetylcholine inhibits it.
Since we have reduced levels of dopamine, we need to reduce our levels of acetylcholine to maintain the balance.
So we take an anticholinergic, I take trihexyphenidyl. I find it helps quite a bit, I can tell the difference if I forget to take it.
This is as I understand it, but I have no medical qualifications, and if anyone knows better, please correct me.
Best wishes for Xmas & the New Year to all
Ron