Which drug blocks sodium channels and reduces transmission by decreasing acetylcholine release at the neuromuscular junction?

Which drug blocks sodium channels and reduces transmission by decreasing acetylcholine release at the neuromuscular junction?

• A. Lidocaine
• B. Magnesium
• C. Atracurium
• D. Dantrolene

Answer: (A)

Blocking voltage-gated sodium channels in neurons stops action potentials from propagating, which reduces the release of acetylcholine at the neuromuscular junction. Lidocaine is a local anesthetic that blocks these sodium channels, dampening nerve impulses and thereby decreasing acetylcholine release from the motor neuron terminals. With less acetylcholine available, transmission to the muscle is diminished. Other options act differently: magnesium lowers acetylcholine release by reducing presynaptic calcium entry rather than blocking sodium channels; atracurium blocks nicotinic receptors on the muscle; dantrolene prevents calcium release from the muscle’s sarcoplasmic reticulum.

Blocking voltage-gated sodium channels in neurons stops action potentials from propagating, which reduces the release of acetylcholine at the neuromuscular junction. Lidocaine is a local anesthetic that blocks these sodium channels, dampening nerve impulses and thereby decreasing acetylcholine release from the motor neuron terminals. With less acetylcholine available, transmission to the muscle is diminished. Other options act differently: magnesium lowers acetylcholine release by reducing presynaptic calcium entry rather than blocking sodium channels; atracurium blocks nicotinic receptors on the muscle; dantrolene prevents calcium release from the muscle’s sarcoplasmic reticulum.