What substance does oxytocin primarily activate in the patient's uterine smooth muscle during labor induction?

Oxytocin primarily activates ligand-gated calcium channels in the uterine smooth muscle during labor induction. This action is crucial because oxytocin facilitates uterine contractions necessary for labor.

When oxytocin is released, it binds to its receptors on the surface of uterine smooth muscle cells, which leads to the activation of signaling pathways that increase intracellular calcium levels. The rise in calcium concentration is pivotal for muscle contraction, as calcium ions bind to calmodulin, leading to the activation of myosin light chain kinase, which subsequently enables actin-myosin interactions that cause contraction.

The other options focus on different mechanisms that are not directly involved in the action of oxytocin on uterine muscle. Understanding the specific role of ligand-gated calcium channels in this context helps clarify why this option is the most relevant for the question about labor induction.