Adrenergic and cholinergic regulation of gastric mucus phospholipid secretion

The influence of adrenergic and cholinergic agonists on phospholipid secretion in gastric mucosal cells maintained in the presence of [3H]choline was investigated. The secretion of [3H]choline phospholipids over a 30-min period averaged 1.98% of the total cellular labeled phospholipids in the absence of any mediator and was enhanced by the beta-adrenergic agonist isoproterenol to a greater extent than by the cholinergic agonist pilocarpine. A 2-fold increase in phospholipid secretion was achieved with isoproterenol, whereas pilocarpine produced a 1.3-fold increase. The stimulatory effect of isoproterenol was inhibited by alprenolol, and that of pilocarpine by atropine. The phospholipids secreted in response to isoproterenol showed a 30% decrease in lysophosphatidylcholine, whereas a 2.1-fold enrichment in this phospholipid occurred with pilocarpine. The results demonstrate the involvement of neural mediators in the regulation of phospholipid secretion in gastric mucus.