“…As recently described by Ward and Kearns, 8 ligand binding (e.g., histamine, gastrin, or acetylcholine) to this acid proton pump creates a 1 million–fold gradient in H + concentration from inside the parietal cell to the gastric lumen, in return for inward transport of K + . Activation of H + ‐K + ‐ATPase is the common final pathway for gastric acid secretion in humans of all ages, 9 , 10 , 11 as reflected by the fact that neonates of 24 weeks gestational age can secrete enough acid to lower the intragastric pH to <4 12 . It is also the pathway that is the mechanistic “target” for PPIs.…”