@article{APS3908,
author = {Meng Yang and Xing-lan Li and Hui-ying Xu and Jia-bin Sun and Bin Mei and Hai-feng Zheng and Lian-hua Piao and De-gang Xing and Zhai-liu Li and Wen-xie Xu},
title = {Role of arachidonic acid in hyposmotic membrane stretch-induced increase in calcium-activated potassium currents in gastric myocytes},
journal = {Acta Pharmacologica Sinica},
volume = {26},
number = {10},
year = {2016},
keywords = {},
abstract = {Aim: To study effects of arachidonic acid (AA) and its metabolites on the hyposmotic membrane stretch-induced increase in calcium-activated potassium currents (IKCa) in gastric myocytes.
Methods: Membrane currents were recorded by using a conventional whole cell patch-clamp technique in gastric myocytes isolated with collagenase.
Results: Hyposmotic membrane stretch and AA increased both IK(Ca) and spontaneous transient outward currents significantly. Exogenous AA could potentiate the hyposmotic membrane stretch-induced increase in IK(Ca). The hyposmotic membrane stretch-induced increase in IK(Ca) was significantly suppressed by dimethyleicosadienoic acid (100 umol/L in pipette solution), an inhibitor of phospholipase A2. Nordihydroguaiaretic acid, a lipoxygenase inhibitor, significantly suppressed AA and hyposmotic membrane stretch-induced increases in IK(Ca). External calcium-free or gadolinium chloride, a blocker of stretch-activated channels, blocked the AA-induced increase in IK(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 IK(Ca); however, heparin, a potent inhibitor of inositol triphosphate receptor, did not block the AA-induced increase in IK(Ca).
Conclusion: Hyposmotic membrane stretch may activate phospholipase A2, which hydrolyzes membrane phospholipids to ultimately produce AA; AA as a second messenger mediates Ca2+ influx, which triggers Ca2+-induced Ca2+ release and elicits activation of IK(Ca) in gastric antral circular myocytes of the guinea pig.},
issn = {1745-7254}, url = {http://www.chinaphar.com/article/view/3908}
}