This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Physiology
Gastric secretion is increased by all except 
Select and explain. 
A. Histamine, B. Acetylcholine, C. Gastrin, D. HCI
D: HCI
Answer: D: HCI 
Explanation: Gastrin, histamine, and acetylcholine are the 3 agonists of the parietal cells.Gastrin and acetylcholine promote secretion by elevating cytosolic free calcium concentration.Histamine increases intracellular cAMP.Both this pathways together have more than additive effect on secretion rates Ref: Ganong&;s Review of medical physiology, 23 rd edition, page 434