Effects of PGE2 in guinea pig colonic myenteric ganglia

PGE2 is a proinflammatory mediator that can influence many cell types. This study was conducted to determine whether PGE2 alters the electrical activity of distal colonic myenteric neurons, because colitis is typically associated with altered motility and changes in neural signaling may be involved. The electrical properties of intact myenteric neurons were evaluated with intracellular microelectrodes. Acute application of PGE2 elicited a prolonged depolarization in both AH and S neurons with little effect on input resistance or electrical excitability. PGE2 effects were suppressed by tetrodotoxin (TTX) or neurokinin (NK) receptor antagonists, indicating that PGE2 acts directly and indirectly to depolarize colonic neurons. PGE2-evoked depolarization was concentration dependent (~3 muM EC50) and was attenuated by the E prostanoid (EP)1/2 receptor antagonist, AH-6809. When preparations were maintained for 48 h in the presence of the stable PGE2 analog PGE2-ethanolamide (10 muM), neurons exhibited a significant membrane depolarization and enhanced excitability. These results suggest that PGE2 can play a role in altered motility in colitis by evoking changes in the electrical properties of myenteric neurons.