Final answer:
Donepezil, a cholinesterase inhibitor, improves cognitive function in Alzheimer's and Parkinson's disease by preventing the breakdown of acetylcholine, enhancing cholinergic neurotransmission, and potentially slowing symptom progression.
Step-by-step explanation:
Donepezil, a cholinesterase inhibitor, is used to treat cognitive impairment in Alzheimer's and Parkinson's disease. This drug blocks the enzyme acetylcholinesterase, which is responsible for breaking down the neurotransmitter acetylcholine in the synapses. By inhibiting this enzyme, donepezil ensures higher levels of acetylcholine in the brain, enhancing cholinergic neurotransmission. This process often results in improved neuronal communication, which can help restore some of the cognitive functions lost in early Alzheimer's disease and may slow the progression of symptoms. Although no cure for Alzheimer's exists, cholinesterase inhibitors like donepezil help manage symptoms and increase quality of life. It's also important to note that maintaining an intellectually and socially active lifestyle may help reduce the risk of developing Alzheimer's disease.