Which neurotransmitter is most associated with Myasthenia Gravis?

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

Answer: (C)

At the neuromuscular junction, acetylcholine is the chemical messenger that binds nicotinic receptors on skeletal muscle to trigger contraction. In Myasthenia Gravis, antibodies attack postsynaptic acetylcholine receptors, reducing their number and function. This makes it harder for the normal amount of acetylcholine released from the nerve to depolarize the muscle fiber, leading to weaker contractions that worsen with use (fatigable weakness). Treatments that boost acetylcholine at the junction, like acetylcholinesterase inhibitors, improve strength, which underscores acetylcholine’s central role in this condition. The other neurotransmitters listed are key players in brain circuits unrelated to the neuromuscular junction, so they aren’t the primary association here.