Role of adrenergic and cholinergic mediators in gastric mucus phospholipid secretion

The role of adrenergic and cholinergic mediators in phospholipid secretion by gastric mucosal cells maintained in the presence of [3H]choline was investigated. The secretion of [3H]choline phospholipids over 30 min period averaged 1.98% of the total cellular labeled phospholipids in the absence of any mediator, and was enhanced by beta-adrenergic agonist, isoproterenol, to a greater extent than the cholinergic agonist, pilocarpine. A 2-fold increase in phospholipid secretion was achieved with isoproterenol, while pilocarpine evoked 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 exhibited a 30% decrease in lysophosphatidylcholine, while 2.1-fold enrichment in this phospholipid occurred with pilocarpine. The results, for the first time, demonstrate the involvement of neural mediators in the regulation of phospholipid secretion in gastric mucus.