Different properties of two mucigogues, pilocarpine and mercuric acetate

Abstract

Hexosamine content of gastric juice and gastric tissue (corpus and antrum separately) was determined in rats an estimation of mucus. Pilocarpine increased mucus secretion thout reducing mucus content of the mucosa. Tissue mucus was even slightly elevated after constant infusion. Rise in juice mucus was not due to contamination from saliva since it persisted after cauterization of salivary gland ducts. Oral administration of mercuric acetate also increased gastric juice mucus but produced a marked depletion of mucus in the mucosa. Whereas pilocarpine did not produce histological alterations in the stomach, after mercuric acetate the mucosa was eroded and clusters of cells were found in the gastric cavity, embedded into a thick layer of mucus. Volume of secretion increased with both compounds. Pilocarpine stimulated acid and pepsin formation at low doses; in contrast, acid secretion was blocked by mercuric acetate and pepsin secretion was markedly reduced. It is concluded that a) mucus secretion can be stimulated by at least two different pathways, neural (pilocarpine being considered as simulating the action of parasympathetic stimulation) and topical (as exemplified by mercuric acetate); b) pilocarpine exerts its mucigogue effect both by eliciting extrusion of mucus granules from the cells and by stimulating mucus synthesis within the same cells, the two processes taking place simultaneously; c) pilocarpine appears to be mucigogue chiefly by acting directly on mucus cells, and not simply through a squeezing-out effect due to the gastric contractions elicited by the drug.