Prostaglandin release from rat stomach following vagal stimulation or administration of acetylcholine.

The rat isolated stomach was perfused via the coeliac artery and prostaglandin-like material released from the mucosa into the lumen (luminal fraction) and from blood vessels and surrounding serosal wall (serosal fraction) was bioassayed using rat fundus strips. Prostaglandin F2 alpha was identified by chromatographic and mass spectrometric techniques. The amount of prostaglandin F2 alpha released upon either vagal nerve stimulation or acetylcholine infusion increased significantly over basal levels, in association with increased gastric peristaltic activity. The quantity of prostaglandin released into the luminal fraction greatly exceeded the amount liberated into the serosal samples and this increase was dependent upon the rate of stimulation. Infusion of either atropine or hexamethonium markedly reduced both the prostaglandin output and the gastric contraction elicited by stimulation. Pretreating the stomach with indomethacin considerably decreased prostaglandin outflow. The role of endogenous prostaglanding F2 alpha in relation to parasympathetic neurotransmission in the stomach is discussed.