Figure 3.

 β‐adrenergic receptors in vascular smooth muscle relaxation. An adrenergic vasodilator via a β₂ adrenergic receptor and G protein (G_s) stimulates adenylyl cyclase (AC) that catalyzes the formation of cyclic adenosine monophosphate (cAMP), leading to vasorelaxation. An endothelial‐dependent vasodilator (β₂ adrenergic, muscarinic, other) binds to its receptor (R) on the surface of the endothelium, resulting in production of nitric oxide (NO), as well as other endothelium‐derived factors (not shown). Produced NO activates guanylyl cyclase (GC) in smooth muscle cells, leading to increases in guanosine monophosphate (cGMP) that induces blood vessel dilation.