Glycoprotein secretion from mouse gallbladder principal cells after chronic variation in parasympathetic activity. A morphometric study after vagotomy and cholinergic superstimulation.

Principal cells of mouse gallbladder epithelium were subjected to quantitative electron microscopic investigation either after superstimulation with pilocarpine for 12 days or 6 weeks after vagotomy at different levels. Cholinergic superstimulation caused a slight hypertrophy of the principal cells, whereas different types of vagotomy induced hypotrophic changes. In the superstimulated animals there was decreased sensitivity to single-dose stimulation with pilocarpine. In contrast, a supersensitivity was recorded in mice subjected to vagotomy. It is concluded that the parasympathetic nervous system is of importance for the regulation of glycoprotein secretion from mouse gallbladder principal cells. The demonstrated vagotomy-induced super-sensitivity may be responsible for an increased glycoprotein release, which in turn may be involved in the formation of gallstones occurring after truncal vagotomy in man.