Question

A male patient with chronic obstructive pulmonary disease (COPD) was prescribed theophylline. He noticed that his urine output had increased the following day. This action of the drug is mediated through which of the following receptors?

• A. Interleukin – 10
• B. Histone deacetylase
• C. Adenosine A1
• D. Beta 2 adrenergic receptors

Answer 1

The Correct Option is C

Theophylline is a medication often used in the treatment of chronic obstructive pulmonary disease (COPD). One of its notable effects is the increase in urine output observed in some patients. This effect is associated with its mechanism of action involving adenosine receptors, specifically the adenosine A1 receptors.

Adenosine A1 receptors are found in various tissues, including the kidneys. Theophylline is known to antagonize (block) these receptors. When adenosine A1 receptors are blocked in the kidneys, it leads to an increase in renal blood flow and a decrease in tubular sodium reabsorption. These changes promote diuresis, which is an increased production of urine.

By reviewing the provided options:

• Interleukin – 10: This is a cytokine with anti-inflammatory properties and does not relate to the urine production effect of theophylline.
• Histone deacetylase: This enzyme is involved in gene expression regulation and is not connected to the urine output mechanism.
• Adenosine A1: Correct answer. Theophylline blocks these receptors, increasing urine output through diuresis.
• Beta 2 adrenergic receptors: These are involved in bronchodilation and are not related to diuretic effects.

Therefore, the increased urine output effect of theophylline is mediated through the adenosine A1 receptors.