Acetylcholine release from the myenteric plexus of guinea-pig ileum by prostaglandin E1

Abstract

Release of acetylcholine (ACh) by prostaglandin E1 from the nerve terminals of the guinea‐pig longitudinal muscle strip was studied in order to reveal the effect of PGE1 on myenteric plexus activity. The ACh released was collected in the presence of physostigmine (2·1 μg ml−1) and choline (0·1 μg ml−1) at 38° C. Five to 100 ng ml−1 PGE1 enhanced the release dose‐dependently. The effect was maintained during the presence of PGE1 in the organ bath, while rapid tachyphylaxis was observed with the ACh‐releasing action of nicotine. Tetrodotoxin or morphine almost completely inhibited the effect of PGE1 on ACh release. Hexamethonium, in a concentration which completely blocked the effect of nicotine, partially inhibited the effect of PGE1. In the late phase of nicotine action, the tissue was still sensitive to PGE1 despite the continued exposure to nicotine. These data suggest the presence in the myenteric plexus of PG receptors which can increase ACh release.

Cyclo‐oxygenase inhibitors antagonize indirectly evoked contractions of the guinea‐pig isolated ileum by inhibiting acetylcholine release

“…Our results are consistent with previous observations that transmural stimulation response is due predominantly to ACh released from parasympathetic nerve endings (Paton & Zar, 1968). (1 Yagasaki et al (1981) have also shown that PGE1 increases resting ACh release from guinea-pig isolated ileum. Enhancement of the contractile power of the transmitter at the postsynaptic membrane cannot be ruled out as an additional factor in the action of PGE2.…”

Effects of H-89, an inhibitor of protein kinase A, on the acetylcholine release from myenteric plexus of guinea pig ileum.

“…PGE also reversed IND-induced inhibition of ACh release (Yagasaki et al, 1981;1984). Thus, the ACh release from myenteric plexus may be modulated by various kinds of endogenous PGs.…”

Role of Cyclic AMP in Prostaglandin-Induced Modulation of Acetylcholine Release from the Myenteric Plexus of Guinea Pig Ileum

“…The longitudinal muscle of the ileum with the myenteric plexus attached was removed as pre viously described (20). The preparation was mounted in an organ bath containing 3 ml of Tyrode's solution of the following composition: 136.9 mM NaCl, 2.7 mM KC1, 1.8 mM CaC12, 1.05 mM MgC12, 11.9 MM NaHCO3, 0.4 mM NaH2PO4 and 5.6 mM glucose.…”