A 30-year-old man complains of progressive muscle weakness and double vision (diplopia) and some difficulty in swallowing solid foods. Neurologic studies show a neuromuscular conduction defect, and diagnostic studies with an intravenous injection of edrophonium are found to rapidly increase his muscle strength. When the patient is treated with neostigmine, his status improves. The most probable target molecule in this treatment is:
A) Acetylcholinesterase
B) Choline acetyltransferase
C) Monoamine oxidase
D) Muscarinic acetylcholine (ACh) receptor
E) Nicotinic ACh receptor

Question

Quizplus · Accepted Answer

The patient's symptoms and the positive response to edrophonium and neostigmine, which are acetylcholinesterase inhibitors, indicate a diagnosis of myasthenia gravis. Acetylcholinesterase is the enzyme targeted by these medications to increase the amount of acetylcholine at the neuromuscular junction, improving muscle strength.

A 30-Year-Old Man Complains of Progressive Muscle Weakness and Double