When a muscle fiber is held at a voltage of 0 mV at the neuromuscular end plate, acetylcholine no longer produces a current because:

When a muscle fiber is held at a voltage of 0 mV at the neuromuscular end plate, acetylcholine no longer produces a current because:

When a muscle fiber is held at a voltage of 0 mV at the neuromuscular end plate, acetylcholine no longer produces a current because:





  1. the acetylcholine receptor channels all close instantly at 0 mV.
  2. an influx of sodium is balanced by an equal efflux of potassium.
  3. the membrane conductance for each permeant ion is 0 at 0 mV.
  4. at 0 mV, the potassium ions lodge in the receptor channel and block the influx of sodium.
  5. the Nernst potentials for both sodium and potassium are 0 mV in muscle fibers.

Answer: 2