Which statement explains why diastolic blood pressure is lower with epinephrine compared to norepinephrine?

Which statement explains why diastolic blood pressure is lower with epinephrine compared to norepinephrine?

• A. Norepinephrine due to alpha vasoconstriction
• B. Epinephrine due to increased heart rate
• C. Norepinephrine due to reflex bradycardia
• D. Epinephrine due to Beta-2 mediated vasomotor relaxation

Answer: (D)

Diastolic pressure mainly reflects the tone of the peripheral arteries during the heart’s relaxing phase. Epinephrine activates beta-2 receptors on vascular smooth muscle, especially in skeletal muscle beds, causing vasodilation. This beta-2–mediated relaxation lowers peripheral resistance during diastole, so diastolic pressure tends to be reduced even as systolic pressure rises from increased heart rate and contractility. Norepinephrine, on the other hand, predominantly increases vascular tone via alpha-1 vasoconstriction, which raises diastolic pressure. So the reason diastolic BP is lower with epinephrine is the Beta-2–mediated vasomotor relaxation.

Diastolic pressure mainly reflects the tone of the peripheral arteries during the heart’s relaxing phase. Epinephrine activates beta-2 receptors on vascular smooth muscle, especially in skeletal muscle beds, causing vasodilation. This beta-2–mediated relaxation lowers peripheral resistance during diastole, so diastolic pressure tends to be reduced even as systolic pressure rises from increased heart rate and contractility. Norepinephrine, on the other hand, predominantly increases vascular tone via alpha-1 vasoconstriction, which raises diastolic pressure. So the reason diastolic BP is lower with epinephrine is the Beta-2–mediated vasomotor relaxation.