What mechanism does Vasopressin utilize when acting as a vasopressor?

Vasopressin, also known as antidiuretic hormone, primarily acts as a vasopressor through the enhancement of peripheral vascular resistance. This occurs via its action on V1 receptors located on vascular smooth muscle, leading to vasoconstriction. The result is an increase in systemic vascular resistance and, consequently, an elevation in blood pressure. In clinical practice, this mechanism makes vasopressin particularly useful in the management of conditions such as septic shock, where vascular tone is compromised.

While fluid retention, increased cardiac contractility, and central nervous system stimulation are effects associated with vasopressin, they are not its primary mechanism as a vasopressor. Fluid retention is more related to its action on the kidneys, promoting water reabsorption in the collecting ducts. Increased cardiac contractility is more commonly associated with agents that stimulate beta-adrenergic receptors, not vasopressin. Central nervous system stimulation is also not a direct effect relevant to its vasopressor actions. Therefore, the focus on peripheral vascular resistance enhancement is key to understanding how vasopressin effectively raises blood pressure during critical care scenarios.