Prompt pump inhibitor suppress gastric acid secretion by acting on:
**Core Concept**
Proton pump inhibitors (PPIs) are a class of medications that suppress gastric acid secretion by irreversibly inhibiting the H+/K+ ATPase enzyme, also known as the gastric proton pump. This enzyme is responsible for the final step of acid production in the parietal cells of the gastric mucosa.
**Why the Correct Answer is Right**
PPIs act by covalently binding to the H+/K+ ATPase enzyme, thereby preventing the exchange of hydrogen ions for potassium ions and ultimately leading to a decrease in gastric acid production. This mechanism of action occurs in the parietal cells of the gastric mucosa, specifically in the canaliculi where the H+/K+ ATPase enzyme is located.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because PPIs do not act on the H2 receptors, which are targeted by histamine-2 receptor antagonists (H2RAs) like ranitidine.
**Option B:** This option is incorrect because PPIs do not inhibit the action of gastrin, a hormone that stimulates gastric acid secretion.
**Option C:** This option is incorrect because PPIs do not work by increasing the production of mucus in the stomach.
**Clinical Pearl / High-Yield Fact**
PPIs have a long duration of action due to their irreversible inhibition of the H+/K+ ATPase enzyme, which can last for several days. This is in contrast to H2RAs, which have a shorter duration of action and may need to be administered multiple times a day.
**Correct Answer:** C. the H+/K+ ATPase enzyme, also known as the gastric proton pump.