Effect of prostaglandin E2 on acetylcholine release from some peripheral cholinergic nerve terminals

The effect of prostaglandin E2 (PGE2) on the acetylcholine (ACh) release evoked from rat phrenic nerve terminals and from Auerbach's plexus of the guinea-pig ileum was investigated. PGE2 enhanced the evoked release of ACh from phrenic nerve terminals and from Auerbach's plexus in a concentration-dependent manner. Preincubation with 7-oxa-13-prostynoic acid, the PGE receptor blocker, and indomethacin inhibited the PGE2-induced increase of evoked release of ACh while atropine failed to do so. Whereas a single administration of either 7-oxa-13-prostynoic acid or indomethacin significantly inhibited the control evoked release of ACh from the Auerbach's plexus, they failed to alter the control evoked release of ACh from the phrenic nerve terminals. The study indicates that the PGE2-induced increase in release of ACh from cholinergic nerve terminals is accomplished through activation of prostaglandin receptors and that PGE2 may play a physiological role in ACh liberation from the cholinergic autonomic nerve terminals but not from motor nerve terminals.