Which statement is true about acetylcholine changes in Parkinson's disease and Alzheimer's disease?

Which statement is true about acetylcholine changes in Parkinson's disease and Alzheimer's disease?

• A. Increased in Parkinson's and decreased in Alzheimer's
• B. Increased in both
• C. Decreased in Parkinson's and increased in Alzheimer's
• D. Decreased in both

Answer: (A)

In Parkinson’s disease, loss of dopaminergic neurons in the nigrostriatal pathway creates an imbalance in the striatum, shifting activity toward acetylcholine. This relative increase in cholinergic activity contributes to many motor symptoms and explains why anticholinergic medications can help with tremor and rigidity. In Alzheimer's disease, there is degeneration of basal forebrain cholinergic neurons, leading to a true deficiency of acetylcholine and contributing to cognitive impairment; acetylcholinesterase inhibitors are used to boost acetylcholine levels and support cognition. Thus, the statement that acetylcholine is increased in Parkinson’s and decreased in Alzheimer’s correctly reflects these opposing neurochemical changes. The other options do not fit the established patterns: both increased, or both decreased, or decreased in Parkinson’s with increased in Alzheimer’s, do not match the underlying biology.

In Parkinson’s disease, loss of dopaminergic neurons in the nigrostriatal pathway creates an imbalance in the striatum, shifting activity toward acetylcholine. This relative increase in cholinergic activity contributes to many motor symptoms and explains why anticholinergic medications can help with tremor and rigidity. In Alzheimer's disease, there is degeneration of basal forebrain cholinergic neurons, leading to a true deficiency of acetylcholine and contributing to cognitive impairment; acetylcholinesterase inhibitors are used to boost acetylcholine levels and support cognition.

Thus, the statement that acetylcholine is increased in Parkinson’s and decreased in Alzheimer’s correctly reflects these opposing neurochemical changes. The other options do not fit the established patterns: both increased, or both decreased, or decreased in Parkinson’s with increased in Alzheimer’s, do not match the underlying biology.