Interplay between the NO pathway and elevated [Ca2+]i enhances ciliary activity in rabbit trachea
Interplay between the NO pathway and elevated [Ca2+]i enhances ciliary activity in rabbit trachea
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DOI：
10.1111/j.1469-7793.1999.179aa.x
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发表时间：
1999-04
期刊：
影响因子：
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通讯作者：
Natalya Uzlaner;Z. Priel
中科院分区：
文献类型：
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作者：
Natalya Uzlaner;Z. Priel
1同时测定了家兔气道纤毛细胞内[Ca ~（2+）]_i和纤毛搏动频率（CBF），以阐明嘌呤能刺激引起纤毛激活的分子事件。2细胞外ATP和细胞外UTP均引起[Ca ~（2+）]i和CBF迅速升高。磷脂酶C抑制剂（U-73122）或苏拉明几乎消除了这些作用。3当GF 109203 X或氯化白屈菜红碱抑制蛋白激酶C（PKC）或RP-腺苷3′，5′-环硫代磷酸三乙胺（RP-cAMPS）抑制蛋白激酶A（PKA）时，细胞外ATP的作用不受影响。4.佛波醇12-肉豆蔻酸酯，13-乙酸酯（TPA）激活PKC对CBF或[Ca 2 +]i的影响很小，而毛喉素或双丁酰cAMP激活PKA导致CBF小幅升高，而不影响[Ca 2 +]i。5当[Ca 2 +]i处于基础水平时，用二丁酰cGMP直接激活蛋白激酶G（PKG）对CBF的影响可忽略不计。然而，当细胞外ATP或离子霉素升高[Ca 2 +]i时，二丁酰cGMP强烈升高CBF。6这些发现表明，细胞外ATP诱导的[Ca 2 +]i的初始升高激活了NO通路，从而导致PKG激活。在持续存在升高的[Ca 2 +]i的刺激PKG，然后诱导CBF的强大增强。与此同时，激活PKG通过一种尚未确定的机制在Ca 2+内流中起着核心作用，因此，通过正反馈，在ATP持续存在的情况下维持CBF接近其最大水平。
1 Average intracellular calcium concentration ([Ca2+]i) and ciliary beat frequency (CBF) were simultaneously measured in rabbit airway ciliated cells in order to elucidate the molecular events that lead to ciliary activation by purinergic stimulation. 2 Extracellular ATP and extracellular UTP caused a rapid increase in both [Ca2+]i and CBF. These effects were practically abolished by a phospholipase C inhibitor (U‐73122) or by suramin. 3 The effects of extracellular ATP were not altered: when protein kinase C (PKC) was inhibited by either GF 109203X or chelerythrine chloride, or when protein kinase A (PKA) was inhibited by RP‐adenosine 3′, 5′‐cyclic monophosphothioate triethylamine (Rp‐cAMPS). 4 Activation of PKC by phorbol 12‐myristate, 13‐acetate (TPA) had little effect on CBF or on [Ca2+]i, while activation of PKA by forskolin or by dibutyryl‐cAMP led to a small rise in CBF without affecting [Ca2+]i. 5 Direct activation of protein kinase G (PKG) with dibutyryl‐cGMP had a negligible effect on CBF when [Ca2+]i was at basal level. However, dibutyryl‐cGMP strongly elevated CBF when [Ca2+]i was elevated either by extracellular ATP or by ionomycin. 6 The findings suggest that the initial rise in [Ca2+]i induced by extracellular ATP activates the NO pathway, thus leading to PKG activation. In the continuous presence of elevated [Ca2+]i the stimulated PKG then induces a robust enhancement in CBF. In parallel, activated PKG plays a central role in Ca2+ influx via a still unidentified mechanism, and thus, through positive feedback, maintains CBF close to its maximal level in the continuous presence of ATP.