Processes in formation of mucus by the body wall of Ariolimax columbianus

Abstract

The mucus secreted by the body surface of the terrestrial pulmonate slug, Ariolimax columbianus, is a variable mix of products of the giant mucous and channel cells of the skin. An in vitro sac preparation allows the study of control and products of these two cell types. Mucins in membrane-bound granules are released by the mucous cells on mechanical or electrical stimulation of the skin. The product of the channel cells is a blood ultrafiltrate, modified by reabsorption of Na⁺ and Cl⁻ ions and transfer into the fluid of K⁺ and HCO₃ ⁻ ions (processes of secretion inhibited by ouabain, amiloride and furosemide; and by other epithelial blocking agents). Rates of secretion can be increased or decreased by gastropod neurotransmitters (acetylcholine, serotonin, and others), and by prostaglandin E₂ and indomethacin.