GO:0060087:   relaxation of vascular smooth muscle
A negative regulation of smooth muscle contraction resulting in relaxation of vascular smooth muscle. The relaxation is mediated by a decrease in the phosphorylation state of myosin light chain. This can be achieved by removal of calcium from the cytoplasm to the sarcoplasmic reticulum lumen through the action of Ca2+ ATPases leading to a decrease myosin light chain kinase activity, and through calcium-independent pathways leading to a increase in myosin light chain phosphatase activity.