The role of cGMP in the regulation of rabbit airway ciliary beat frequency
The role of cGMP in the regulation of rabbit airway ciliary beat frequency
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DOI：
10.1113/jphysiol.2003.041707
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发表时间：
2003-09-15
影响因子：
5.5
通讯作者：
Sanderson, MJ
中科院分区：
文献类型：
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作者：
Zhang, L;Sanderson, MJ
环鸟苷 3',5-单磷酸 (cGMP) 和 cGMP 依赖性蛋白激酶 (PKG) 的参与以及它们与 Ca2+ 依赖性机制在纤毛活动调节中的相互作用尚不清楚。为了研究 cGMP 如何调节纤毛活动，使用数字高速相差和荧光成像同时量化兔气管纤毛细胞响应 8-溴-cGMP (Br-cGMP) 的纤毛跳动频率 (CBF) 和细胞内钙浓度 ([Ca2+](i)) 的变化。 Br-cGMP 诱导纤毛活动的反应，该反应可分为两部分。首先，Br-cGMP 诱导基础 CBF 出现浓度依赖性增加，但并未增加 [Ca2+](i)。该反应不受 BAPTA 过度缓冲 [Ca2+](i) 的影响，但被 PKG 抑制剂 KT5823 消除。其次，Br-cGMP 诱导 CBF 的一系列短暂增加，叠加在 CBF 的持续增加上。 CBF 的这些瞬时增加与 [Ca2+](i) 的一系列瞬时增加的刺激相关，并且被 BAPTA 消除，但不受 KT5823 的影响。 CBF 和 [Ca2+](i) 瞬时增加的幅度不依赖于 Br-cGMP 的浓度。由离子霉素或 ATP 诱导的 CBF 的 Ca2+ 依赖性变化不受 KT5823 的影响。根据这些结果，我们提出 cGMP 通过两种方式增加 CBF：首先通过涉及 PKG 的 Ca2+ 独立机制，其次通过刺激 [Ca2+](i) 变化后的 Ca2+ 依赖机制。此外，我们认为 Ca2+ 依赖性的兔气道纤毛活动刺激最初并不需要 PKG 激活。
The involvement of cyclic guanosine 3',5-monophosphate (cGMP) and cGMP-dependent protein kinase (PKG) and their interaction with the Ca2+-dependent mechanisms in the regulation of ciliary activity are not well understood. To investigate how cGMP regulates ciliary activity, changes in ciliary beat frequency (CBF) and intracellular calcium concentration ([Ca2+](i)) of rabbit tracheal ciliated cells in response to 8-bromo-cGMP (Br-cGMP) were simultaneously quantified using digital, high-speed phase-contrast and fluorescence imaging. Br-cGMP induced a response in ciliary activity that could be separated into two parts. Firstly, Br-cGMP induced a concentration-dependent increase in the basal CBF that occurred without increasing the [Ca2+](i). This response was not affected by excessively buffering the [Ca2+](i) with BAPTA but was abolished by KT5823, a PKG inhibitor. Secondly, Br-cGMP induced a series of transient increases in CBF that were superimposed on the sustained increases in CBF. These transient increases in CBF correlated with the stimulation of a series of transient increases in [Ca2+](i) and were abolished by BAPTA, but were unaffected by KT5823. The magnitude of the transient increases in CBF and [Ca2+](i) were not dependent on the concentration of Br-cGMP. The Ca2+-dependent changes in CBF induced by ionomycin or ATP were not affected by KT5823. From these results, we propose that cGMP increases CBF in two ways: firstly through a Ca2+-independent mechanism involving PKG, and secondly through a Ca2+-dependent mechanism following the stimulation of changes in [Ca2+](i). In addition, we suggest that the Ca2+-dependent stimulation of rabbit airway ciliary activity does not initially require PKG activation.