Which mechanism contributes to epinephrine 1:1000 increasing blood pressure?

• A. Increased cardiac contractility
• B. Peripheral vasodilation
• C. Decreased heart rate
• D. Increased parasympathetic tone

Answer: (A)

Epinephrine raises blood pressure by stimulating the heart to pump more forcefully. When beta-1 receptors in the heart are activated, the heart’s contractility increases, which raises the stroke volume. With a higher stroke volume, cardiac output goes up, leading to higher arterial pressure. While epinephrine also causes vasoconstriction through alpha-1 receptors, the option that most directly explains the rise in blood pressure from the heart’s perspective is increased cardiac contractility. In contrast, peripheral vasodilation would lower blood pressure, decreased heart rate would reduce it, and increased parasympathetic tone would dampen the heart’s activity, all of which would not raise blood pressure.