Indirect MOA of ephedrine interacts with which receptors?

Indirect MOA of ephedrine interacts with which receptors?

• A. Alpha-1, Alpha-2, and Beta-1 receptors
• B. Alpha-1, Alpha-2, Beta-1, and Beta-2 receptors
• C. Alpha-1 and Beta-1 receptors
• D. Beta-2 receptors only

Answer: (A)

Ephedrine’s indirect action works by promoting the release of norepinephrine from sympathetic nerve endings, and that norepinephrine then activates certain adrenergic receptors. The norepinephrine released preferentially stimulates alpha-1 and alpha-2 receptors, and beta-1 receptors. Activation of alpha-1 increases vascular tone, alpha-2 provides modulatory control over further release, and beta-1 raises heart rate and contractility. Beta-2 activation is not strongly driven by norepinephrine, so it’s not a primary target of the indirect mechanism. Therefore, the indirect MOA interacts with alpha-1, alpha-2, and beta-1 receptors. (Note: ephedrine also has direct receptor agonist effects, including some beta-2 activity, but that is a separate, direct mechanism.)

Ephedrine’s indirect action works by promoting the release of norepinephrine from sympathetic nerve endings, and that norepinephrine then activates certain adrenergic receptors. The norepinephrine released preferentially stimulates alpha-1 and alpha-2 receptors, and beta-1 receptors. Activation of alpha-1 increases vascular tone, alpha-2 provides modulatory control over further release, and beta-1 raises heart rate and contractility. Beta-2 activation is not strongly driven by norepinephrine, so it’s not a primary target of the indirect mechanism. Therefore, the indirect MOA interacts with alpha-1, alpha-2, and beta-1 receptors. (Note: ephedrine also has direct receptor agonist effects, including some beta-2 activity, but that is a separate, direct mechanism.)