Isoproterenol tends to decrease mean arterial pressure (MAP) due to what effect?

Isoproterenol tends to decrease mean arterial pressure (MAP) due to what effect?

• A. Increased systemic vascular resistance
• B. Increased venous return
• C. Decreased systemic vascular resistance
• D. No effect on vascular tone

Answer: (C)

Isoproterenol lowers MAP mainly through its vascular effects. It acts as a beta-adrenergic agonist that stimulates beta-2 receptors in vascular smooth muscle, causing vasodilation and a drop in systemic vascular resistance. Although it also increases heart rate and contractility via beta-1 effects, which raises cardiac output, the decrease in afterload from reduced SVR tends to dominate, leading to an overall fall in mean arterial pressure. In short, the key mechanism is decreased systemic vascular resistance due to beta-2–mediated vasodilation.

Isoproterenol lowers MAP mainly through its vascular effects. It acts as a beta-adrenergic agonist that stimulates beta-2 receptors in vascular smooth muscle, causing vasodilation and a drop in systemic vascular resistance. Although it also increases heart rate and contractility via beta-1 effects, which raises cardiac output, the decrease in afterload from reduced SVR tends to dominate, leading to an overall fall in mean arterial pressure. In short, the key mechanism is decreased systemic vascular resistance due to beta-2–mediated vasodilation.