Sympathomimetics · Pharmacology

Phenylephrine causes a rise in blood pressure, which often results in a compensatory 'reflex bradycardia'. Which receptor is primarily responsible for the initial pressor response?

  1. Alpha-2
  2. Beta-1
  3. Alpha-1
  4. Beta-2
Show answer and explanation

Correct answer: Alpha-1

Phenylephrine is a selective Alpha-1 agonist that causes potent peripheral vasoconstriction. The resulting increase in systemic vascular resistance triggers the baroreceptor reflex, which increases vagal tone to slow the heart rate.

Difficulty: Medium Question 6 of 20

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