What is the mechanism through which Benztropine and Trihexyphenidyl improve symptoms of Parkinson's disease?

The mechanism through which Benztropine and Trihexyphenidyl improve symptoms of Parkinson's disease is primarily linked to their ability to inhibit acetylcholine production. In Parkinson's disease, there is a deficiency of dopamine due to the degeneration of dopaminergic neurons in the substantia nigra. This results in an imbalance between acetylcholine, which is excitatory, and dopamine, which is inhibitory.

By inhibiting acetylcholine, Benztropine and Trihexyphenidyl help to restore the balance between these two neurotransmitters, thereby alleviating symptoms such as tremors and rigidity. This anticholinergic action reduces the excessive cholinergic activity that occurs due to decreased dopaminergic activity, leading to an improvement in motor function.

The other options do not reflect the correct mechanism. Blocking dopamine receptors would further exacerbate the symptoms of Parkinson's disease, as it would inhibit the already low levels of dopamine. Increasing serotonin levels does not have a primary role in the treatment of Parkinson's disease, as serotonin dysregulation is not a core characteristic of the condition. Restoring dopamine levels in the brain is more closely associated with dopaminergic therapies (such as Levodopa) rather than the specific mechanism of