Extraneural cholinergic markers in Alzheimer's and Parkinson's disease

Muscarinic and nicotinic binding sites were analysed in lymphocytes from patients with Alzheimer's disease, Multi-infarct dementia, Parkinson's disease and age- matched controls. A significant decrease in the number of both muscarinic and nicotinic binding sites was obtained in lymphocytes from Alzheimer patients while in Parkinson patients a significant decrease was found only in the nicotinic binding sites. Using butyrylthiocholine as substrate, no change was observed in cholinesterase activity in plasma from Alzheimer patients, whereas a significant decrease in plasma cholinesterase activity was found in Parkinson patients.