This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autacoids, Subject name: Pharmacology
Histamine blocker in stomach act through 
Select and explain. 
A. Decreasing cAMP in stomach, B. Increasing cAMP in stomach, C. Increasing IP3 in stomach, D. Decreasing IP3 in stomach
D: Decreasing IP3 in stomach
Answer: D: Decreasing IP3 in stomach 
Explanation: Histamine H2 blockersinhibit the action of histamine ongastric H2 receptors thereby decreasing gastric acidity. They were considered a breakthrough in the treatment of peptic ulcer disease when first introduced. Refer kDT 6/e 153