Muscle membrane will depolarize in response to acetylcholine binding its receptors at the neuromuscular junction. Associated with this depolarization are changes in glycogen metabolism in skeletal muscle cells. Which of the following represents the correct changes in enzyme activity seen in response to acetylcholine binding?

Question

Quizplus · Accepted Answer

Acetylcholine binding leads to muscle contraction, which increases intracellular calcium levels. Calcium binds to the calmodulin subunit of glycogen phosphorylase kinase, activating it and thus increasing its activity.  Muscle contraction results in release of stored calcium ion from sarcoplasmic reticulum. The released calcium binds to the calmodulin subunit of glycogen synthase-phophorylase kinase resulting in activation of this regulatory enzyme. The net effect is enhanced activity of phosphorylase and inhibited activity of glycogen synthase.

Muscle Membrane Will Depolarize in Response to Acetylcholine Binding Its