Angiotensin II has what effect on norepinephrine release from presynaptic neurons?

Angiotensin II has what effect on norepinephrine release from presynaptic neurons?

• A. No effect
• B. Increases NE release
• C. Decreases NE release
• D. Vasodilation

Answer: (B)

Angiotensin II increases norepinephrine release from presynaptic neurons by acting on AT1 receptors on sympathetic nerve terminals. This receptor activation boosts calcium influx and promotes exocytosis of norepinephrine, increasing its presence in the synaptic cleft and enhancing sympathetic signaling. The net effect helps drive vasoconstriction and raise blood pressure, illustrating how RAAS activation amplifies sympathetic tone. It isn’t a no-effect action, it isn’t a decrease in release, and vasodilation isn’t the mechanism by which norepinephrine release is modulated.

Angiotensin II increases norepinephrine release from presynaptic neurons by acting on AT1 receptors on sympathetic nerve terminals. This receptor activation boosts calcium influx and promotes exocytosis of norepinephrine, increasing its presence in the synaptic cleft and enhancing sympathetic signaling. The net effect helps drive vasoconstriction and raise blood pressure, illustrating how RAAS activation amplifies sympathetic tone. It isn’t a no-effect action, it isn’t a decrease in release, and vasodilation isn’t the mechanism by which norepinephrine release is modulated.