Donepezil primarily increases the activity of which neurotransmitter system?

• A. Acetylcholine
• B. Glutamate
• C. Dopamine
• D. Serotonin

Answer: (A)

Donepezil works by boosting acetylcholine signaling in the brain. It is an acetylcholinesterase inhibitor, so it blocks the enzyme that breaks down acetylcholine in the synaptic cleft. With less breakdown, acetylcholine levels stay elevated longer, enhancing cholinergic transmission. This helps counteract the cholinergic neuron loss associated with Alzheimer's disease and can modestly improve memory and cognitive function. The other neurotransmitter systems—glutamate, dopamine, and serotonin—are not the primary targets of donepezil, though other drugs in the spectrum of dementia treatments may interact with or modulate those systems in different ways.