Systemic adrenergic agonists can act on which receptor types?

• A. A2 receptors
• B. B2 receptors
• C. Dopamine receptors
• D. All of the above

Answer: (D)

Systemic adrenergic agonists can engage multiple receptor types depending on the drug and the dose. Some agents stimulate alpha-2 receptors, which can reduce sympathetic outflow, while others activate beta-2 receptors, producing bronchodilation or vasodilation in smooth muscle. Dopamine itself acts on dopamine receptors at certain doses, and at higher doses can interact with adrenergic receptors as well. Because these drugs are capable of affecting more than one receptor family in different tissues, all of the listed receptor types can be targeted by systemic adrenergic agonists.