This study was undertaken to develop an easily reproducible gastric mucus secretory model that would elicit maximal mucus secretion without gross mucosal injury. Acetylcholine chloride (50 micrograms/min) was infused intraarterially into a chambered wedge of exteriorized corpus mucosa via a branch of the gastrosplenic artery for 1 h. An alkaline secretion, pH 8.28 +/- 0.48, was produced and consisted of water (40-60 ml/h), electrolytes (Na+, K+, Cl-), soluble mucus, and a mucus gel (4-10 mm thick). Mucus was quantitated by monitoring the secretion of newly synthesized glycoproteins, radiolabeled with [3H]glucosamine and sodium [35S]sulfate. A transient increase in deoxyribonucleic acid efflux, and mucosal permeability as measured by albumin movement, occurred, both of which were reversible upon cessation of acetylcholine chloride infusion. The gastric epithelium was normal histologically, except for occasional apical vacuoles present only in interfoveolar mucus cells. Transmission electron microscopy revealed diminished numbers of apical mucus granules and greatly enlarged intercellular spaces in some mucus cells. Histochemically, the mucus gel consisted of alternating layers of sulfate-rich and sulfate-poor glycoproteins. This model provides a copious amount of mucus that is ideal for biochemical analysis and determination of mucus structure. It allows one to distinguish soluble mucus, gel mucus, and unsecreted granule-bound mucus.