Which statement best describes the effects of the negative enantiomer of dobutamine?

Which statement best describes the effects of the negative enantiomer of dobutamine?

• A. Beta-1 and Beta-2 agonism with Alpha-1 antagonist
• B. Beta-1 and Beta-2 agonism with Alpha-1 agonist
• C. No beta receptor activity
• D. Vasoconstrictive effect outweighs others

Answer: (B)

Enantiomer-specific receptor activity drives the effects. The negative (levorotatory) enantiomer of dobutamine engages multiple adrenergic receptors, including beta-1 and beta-2 as well as alpha-1. That means it can increase cardiac contractility through beta-1 stimulation, have some vascular effects via beta-2, and cause vasoconstriction through alpha-1. The combination results in a mixed hemodynamic profile rather than a pure beta-1 effect or a lack of beta activity. That’s why the best description is beta-1 and beta-2 agonism with alpha-1 agonist activity.

Enantiomer-specific receptor activity drives the effects. The negative (levorotatory) enantiomer of dobutamine engages multiple adrenergic receptors, including beta-1 and beta-2 as well as alpha-1. That means it can increase cardiac contractility through beta-1 stimulation, have some vascular effects via beta-2, and cause vasoconstriction through alpha-1. The combination results in a mixed hemodynamic profile rather than a pure beta-1 effect or a lack of beta activity. That’s why the best description is beta-1 and beta-2 agonism with alpha-1 agonist activity.