抄録
Mucin exocytosis from antral mucous cells of guinea pig is maintained by an autocrine mechanism via prostaglandin E2 (PGE2) during acetylcholine (ACh) stimulation. Indomethacin (IDM) or aspirin (ASA) partially inhibited the frequency of ACh -stimulated exocytotic events. However, the IDM-induced decrease in the frequency of ACh-stimulated exocytotic events was 40%, while ASA-induced decrease was 60%. Inhibition of PKA effects by ONO8713 (100 μM, an inhibitor of EP receptors) or H-89 also decreased the frequency by 60%. The COX synthesizes PGE2 and 15(R)-HPETE from arachidonic acid (AA), and IDM inhibits both productions, however, ASA inhibits only PGE2 production. This suggests that IDM may accumulate AA. In ASA-treated cells, IDM increased the frequency of ACh-stimulated exocytotic events similar to that observed in IDM-treated cells. IDM alone increased the frequency of exocytotic events. The IDM-induced increases, which were eliminated by AACOCF3 (100 μM, an inhibitor of phospholipase A2), were mimicked by AA. Moreover, AA effects were mimicked by WY14643 (an agonist of peroxisome proliferator-activated receptors, PPARs). The present study suggests that accumulation of AA may enhance the Ca2+-regulated exocytosis via PPARs in IDM-treated antral mucous cell. [Jpn J Physiol 55 Suppl:S73 (2005)]
