| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Internal Medicine (Div. II), Osaka Medical College, Takatsuki, Osaka, Japan
2 Department of Physiology, Osaka Medical College, Takatsuki, Osaka, Japan
3 Department of Chemistry, Osaka Medical College, Takatsuki, Osaka, Japan
4 Department of Pathology, Osaka Medical College, Takatsuki, Osaka, Japan
* To whom correspondence should be addressed. E-mail: takan{at}art.osaka-med.ac.jp.
The effects of indomethacin (IDM) and aspirin (ASA) on acetylcholine (ACh, 10 µM) -stimulated exocytotic events were studied in guinea pig antral mucous cells using video optical microscopy. IDM or ASA, which inhibits cyclo-oxygenase (COX), decreased the frequency of ACh-stimulated exocytotic events by 30 % or 60 %, respectively. The extent of inhibition induced by ASA (60 %) decreased by 30 %, when IDM or arachidonic acid (AA, the substrate of COX) was added. IDM, unlike ASA, appears to induce the accumulation of AA, which enhances the frequency of ACh-stimulated exocytotic events in ASA-treated cells. ONO-8713 (100 µM, an inhibitor of EP receptor) and H-89 (20 µM, an inhibitor of protein kinase A) also decreased the frequency of ACh-stimulated exocytotic events by 60 %. However, the supplementation of PGE2 (1 µM) prevented the IDM-induced decrease in the frequency of ACh-stimulated exocytotic events. SC-560 (an inhibitor of COX-1) decreased the frequency of ACh-stimulated exocytotic events by 30 %, but NS-398 (an inhbitor of COX-2) did not. Moreover, IDM decreased the frequency of exocytotic events stimulated by ionomycin, suggesting that COX-1 activity is stimulated by an increase in intracellular Ca2+ concentration ([Ca2+]i). ACh and ionomycin increased PGE2 release in antral mucosal cells. In conclusion, in ACh-stimulated antral mucous cells, an increase in [Ca2+]i activates Ca2+-regulated exocytotic events and PGE2 release mediated by COX-1. The released PGE2 induces the accumulation of cAMP, which enhances the Ca2+- regulated exocytosis. The autocrine mechanism mediated by PGE2 maintains the high-level mucin release from antral mucous cells during ACh stimulation.
This article has been cited by other articles:
|
|
 |
|
  C. Shimamoto, E. Umegaki, K.-i. Katsu, M. Kato, S. Fujiwara, T. Kubota, and T. Nakahari [Cl ]i modulation of Ca2+-regulated exocytosis in ACh-stimulated antral mucous cells of guinea pig Am J Physiol Gastrointest Liver Physiol, October 1, 2007; 293(4): G824 - G837. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Shimamoto, Y. Nakanishi, K.-i. Katsu, T. Nakano, T. Kubota, H. Mori, and T. Nakahari Prostaglandin E2 release in gastric antral mucosa of guinea-pigs: basal PGE2 release by cyclo-oxygenase 2 and ACh-stimulated PGE2 release by cyclo-oxygenase 1 Exp Physiol, November 1, 2006; 91(6): 1015 - 1024. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. H. Saad, C. Shimamoto, T. Nakahari, S. Fujiwara, K.-i. Katsu, and Y. Marunaka cGMP modulation of ACh-stimulated exocytosis in guinea pig antral mucous cells Am J Physiol Gastrointest Liver Physiol, June 1, 2006; 290(6): G1138 - G1148. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Fujiwara, C. Shimamoto, Y. Nakanishi, K.-i. Katsu, M. Kato, and T. Nakahari Enhancement of Ca2+-regulated exocytosis by indomethacin in guinea-pig antral mucous cells: arachidonic acid accumulation Exp Physiol, January 1, 2006; 91(1): 249 - 259. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
