Activation of muscarinic receptors in porcine airway smooth muscle elicits a transient increase in phospholipase D activity.
Activation of muscarinic receptors in porcine airway smooth muscle elicits a transient increase in phospholipase D activity.
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猪气道平滑肌中毒蕈碱受体的激活引起磷脂酶 D 活性的短暂增加。
DOI：
10.1007/bf02256440
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发表时间：
1999
影响因子：
11
通讯作者：
Farley,JM
中科院分区：
文献类型：
--
作者：
Mamoon,AM;Smith,J;Baker,RC;Farley,JM
磷脂酶D （Phospholipase D， PLD）是一种催化磷脂酰胆碱水解生成磷脂酸和胆碱的磷酸二酯酶。在乙醇存在的情况下，PLD还催化磷脂酰乙醇的形成，这是该酶的独特特性。用[3H]棕榈酸标记猪气管平滑肌后，通过测定[3H]磷脂酸（[3H]PA）和[3H]磷脂乙醇（[3H]PEth）的生成，研究了毒菌碱受体诱导的PLD活性变化。当用100 mM乙醇预处理时，胆碱能受体激动剂乙酰胆碱（Ach）显著但短暂地以浓度依赖的方式增加[3H]PA和[3H]PEth的形成（在10 - 6至10-4M Ach存在时，与对照组相比，浓度为105-400%）。阿托品抑制了乙酰胆碱受体介导的PLD活性增加（10-6M），表明PLD的激活是通过毒蕈碱受体发生的。phorboll -12-肉豆蔻酸酯-13-乙酸酯（PMA）激活蛋白激酶C （PKC）可增加PLD活性，而PKC抑制剂calphostin C（10 - 8至10-6M）和GFX（10 - 8至10-6M）可有效阻断PLD活性。GFX和calphostin c也显著但不完全地抑制了疼痛诱导的PLD活性的增加。根据目前的数据，我们得出结论，在气管平滑肌中，毒蕈碱乙酰胆碱受体诱导的PLD激活本质上是短暂的，并通过PKC与这些受体偶联。然而，PKC激活并不是疼痛诱导的猪气管平滑肌PLD激活的唯一原因。
Phospholipase D (PLD) is a phosphodiesterase that catalyses hydrolysis of phosphatidylcholine to produce phosphatidic acid and choline. In the presence of ethanol, PLD also catalyses the formation of phosphatidylethanol, which is a unique characteristic of this enzyme. Muscarinic receptor-induced changes in the activity of PLD were investigated in porcine tracheal smooth muscle by measuring the formation of [3H]phosphatidic acid ([3H]PA) and [3H]phosphatidylethanol ([3H]PEth) after labeling the muscle strips with [3H]palmitic acid. The cholinergic receptor agonist acetylcholine (Ach) significantly but transiently increased formation of both [3H]PA and [3H]PEth in a concentration-dependent manner (>105–400% vs. controls in the presence of 10–6to 10–4M Ach) when pretreated with 100 mM ethanol. The Ach receptor-mediated increase in PLD activity was inhibited by atropine (10–6M), indicating that activation of PLD occurred via muscarinic receptors. Activation of protein kinase C (PKC) by phorbol-12-myristate-13-acetate (PMA) increased PLD activity that was effectively blocked by the PKC inhibitors calphostin C (10–8to 10–6M) and GFX (10–8to 10–6M). Ach-induced increases in PLD activity were also significantly, but incompletely, inhibited by both GFX and calphostin C. From the present data, we conclude that in tracheal smooth muscle, muscarinic acetylcholine receptor-induced PLD activation is transient in nature and coupled to these receptors via PKC. However, PKC activation is not solely responsible for Ach-induced activation of PLD in porcine tracheal smooth muscle.