The observation that the acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it is an example of
A) a voltage-gated sodium channel.
B) a voltage-gated potassium channel.
C) a ligand-gated sodium channel.
D) a second-messenger-gated sodium channel.
E) a chemical that inhibits action potentials.

Question

Quizplus · Accepted Answer

The observation of acetylcholine binding to a sodium channel suggests that it is a ligand-gated sodium channel. Voltage-gated sodium channels open in response to changes in membrane potential and are not directly affected by neurotransmitters or ligands. Potassium channels can also be voltage-gated or ligand-gated, but acetylcholine specifically binds to sodium channels at this junction. Second-messenger gating occurs when a neurotransmitter binds to a receptor and triggers an intracellular signaling cascade, but this is not observed in this scenario. Finally, the observation does not suggest that a chemical inhibiting action potentials is involved.

The Observation That the Acetylcholine Released into the Junction Between