n. pl. locÂ·ules or locÂ·uÂ·li (-lÄ«â²). A small cavity or compartment within an organ or part of an animal or plant, as any of the cavities within a plant ovary. [Latin.
Competitive inhibition is a form of enzyme inhibition where binding of the inhibitor to the active site on the enzyme prevents binding of the substrate and vice versa. Most competitive inhibitors function by binding reversibly to the active site of the enzyme.
H 2 blockers. These drugs (cimetidine, ranitidine, famotidine, available IV and orally; and nizatidine available orally) are competitive inhibitors of histamine at the H2 receptor, thus suppressing gastrin-stimulated acid secretion and proportionately reducing gastric juice volume.