Vasopressin has actions on beta-adrenergic receptors.

Vasopressin has actions on beta-adrenergic receptors.

• A. True
• B. Only with epinephrine
• C. Only at high concentrations
• D. False

Answer: (D)

Vasopressin acts through vasopressin receptors rather than beta-adrenergic receptors. Its primary effects come from binding V1 receptors on vascular smooth muscle, causing vasoconstriction via the phospholipase C–IP3/DAG pathway, and from binding V2 receptors in the kidney to promote water reabsorption. Because it does not directly engage beta-adrenergic receptors, the statement is false. It can enhance the overall pressor response in shock when used with catecholamines, but this is not due to beta-receptor activation, and it does not require epinephrine exposure or high concentrations to act.

Vasopressin acts through vasopressin receptors rather than beta-adrenergic receptors. Its primary effects come from binding V1 receptors on vascular smooth muscle, causing vasoconstriction via the phospholipase C–IP3/DAG pathway, and from binding V2 receptors in the kidney to promote water reabsorption. Because it does not directly engage beta-adrenergic receptors, the statement is false. It can enhance the overall pressor response in shock when used with catecholamines, but this is not due to beta-receptor activation, and it does not require epinephrine exposure or high concentrations to act.