磷脂酶A_2激活与氨甲酰胆碱所致CCL137人胚肺成纤维细胞中M-胆碱受体隐没的关系(英文)

Involvement of phospholipase A_2 activation in carbachol-induced sequestration of muscarinic acetylcholine receptors in CCL137 human embryonic lung fibroblasts'

氨甲酰胆碱（CCh)可使事先以[^3H]花生四烯酸充分标记的CCL137细胞释放的花生四烯酸量明显增多，经CCh处理的CCL137细胞，其质膜中磷脂酶A2（PLA2）的活性明显增高：PLA2及其激活剂蜂毒肽都能像CCh处理一样，降低CCL137细胞与[^3H]NMS的结合作用；PLA2的非竞争性抑制剂米帕林能有效地减轻CCh所致细胞对[^3H]NMS结合的降低，以上结果表明，质膜中PLA2激活可能在CCh所致CCL137细胞的M-受体隐没中起重要作用，PLA2激活还与CCh所致CCL137细胞中磷脂酰肌醇代谢增强有关。

Carbachol (CCh) resulted in a significant increase of arachidonic acid release from CCL137 cells which were preincubated with radiolabeled arachidonic acid. The membranes prepared from CCh-treated cells displayed much higher phospholipase A2 (PLA2) activity as compared with those of the control. PLA2 and its activator, melittin, as well as CCh significantly decreased the binding of [3H]N-methyl-scopolamine ([3H]NMS) to CCL137 cells. The noncompetitive inhibitor of PLA2. mepacrine, has been demonstrated to be effective in diminishing the effect of CCh on [3H]NMS binding to the cells. All of the results mentioned above suggest that the activation of PLA2 in plasma membranes most likely plays an important role in CCh-induced mAChR sequestration in CCL137 cells. The activation of PLA2 may account for the enhancement of PI turnover which is abolished by rnepacrine.