CVS Practice Test 2025 – The All-In-One Guide to Exam Success!

The correct answer is based on the role of cAMP (cyclic adenosine monophosphate) in the signaling pathways associated with beta-2 adrenergic receptors. When catecholamines such as epinephrine bind to beta-2 receptors located on the vascular smooth muscle of skeletal muscle, this interaction activates the enzyme adenylate cyclase. This enzyme catalyzes the conversion of ATP to cAMP.

cAMP serves as a critical second messenger that facilitates the process of vasodilation. It activates protein kinase A (PKA), which leads to a series of phosphorylations that ultimately result in the relaxation of smooth muscle cells. This vasodilation is essential for increasing blood flow to skeletal muscles during times of increased demand, such as during exercise.

Furthermore, cAMP plays a distinct role compared to the other second messengers listed. DAG (diacylglycerol) and IP3 (inositol trisphosphate) are more commonly associated with pathways that lead to increased intracellular calcium levels and muscle contraction rather than relaxation. Additionally, while calcium itself is vital for muscle contraction processes, it does not specifically relate to the vasodilatory effects mediated by beta-2 receptor activation. Thus, the promotion of vasodilation by