Furosemide acts by inhibiting –
**Core Concept**
Furosemide is a **loop diuretic** that acts on the kidneys to increase urine production. It works by inhibiting a specific transport mechanism in the renal tubules. This action is crucial for its role in treating conditions like **edema** and **hypertension**.
**Why the Correct Answer is Right**
The correct answer involves the inhibition of the **Na+-K+-2Cl- cotransporter** (NKCC2) in the thick ascending limb of the **loop of Henle**. This inhibition prevents the reabsorption of sodium, potassium, and chloride ions, leading to increased excretion of water and ions. The **NKCC2** is a key target for **furosemide**.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not involve the specific mechanism of furosemide.
**Option B:** Incorrect as it is unrelated to the action of loop diuretics.
**Option C:** Incorrect because, although it involves ion transport, it is not the primary mechanism of furosemide.
**Clinical Pearl / High-Yield Fact**
Remember, **loop diuretics** like furosemide are highly effective in treating **edema** associated with **heart failure** and **nephrotic syndrome**. Their action on the **loop of Henle** makes them potent diuretics.
**Correct Answer:** D. Na+-K+-2Cl- cotransporter