| Autor: |
Meng, Yang, Xing-lan, Li, Hui-ying, Xu, Jia-bin, Sun, Bin, Mei, Hai-feng, Zheng, Lian-hua, Piao, De-gang, Xing, Zhai-liu, Li, Wen-xie, Xu |
| Rok vydání: |
2005 |
| Předmět: |
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| Zdroj: |
Acta pharmacologica Sinica. 26(10) |
| ISSN: |
1671-4083 |
| Popis: |
To study effects of arachidonic acid (AA) and its metabolites on the hyposmotic membrane stretch-induced increase in calcium-activated potassium currents (I(KCa)) in gastric myocytes.Membrane currents were recorded by using a conventional whole cell patch-clamp technique in gastric myocytes isolated with collagenase.Hyposmotic membrane stretch and AA increased both I(K(Ca))) and spontaneous transient outward currents significantly. Exogenous AA could potentiate the hyposmotic membrane stretch-induced increase in I(K(Ca)). The hyposmotic membrane stretch-induced increase in I(K(Ca)) was significantly suppressed by dimethyleicosadienoic acid (100 micromol/L in pipette solution), an inhibitor of phospholipase A2. Nordihydroguaiaretic acid, a lipoxygenase inhibitor, significantly suppressed AA and hyposmotic membrane stretch-induced increases in I(K(Ca)). External calcium-free or gadolinium chloride, a blocker of stretch-activated channels, blocked the AA-induced increase in I(K(Ca)) significantly, but it was not blocked by nicardipine, an L-type calcium channel blocker. Ryanodine, a calcium-induced calcium release agonist, completely blocked the AA-induced increase in I(K(Ca)); however, heparin, a potent inhibitor of inositol triphosphate receptor, did not block the AA-induced increase in I(K(Ca)).Hyposmotic membrane stretch may activate phospholipase A2, which hydrolyzes membrane phospholipids to ultimately produce AA; AA as a second messenger mediates Ca(2+) influx, which triggers Ca(2+)-induced Ca(2+) release and elicits activation of I(K(Ca)) in gastric antral circular myocytes of the guinea pig. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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