Regulation of by protein kinases of CFTR chloride current and the acidic pH-activated chloride current in cardiac myocytes

心肌细胞中 CFTR 氯电流和酸性 pH 激活氯电流的蛋白激酶调节

• 批准号: 17500276
• 负责人: EHARA Tsuguhisa
• 金额: $ 2.39万
• 依托单位: Saga University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17500276/
• 关键词: Cardiac myocvtes; chloride current; pH; acidic pH-induced current; PKA; PKC; ATP; P2-purinergic receptor; CFTR; P_<2Y>受容体; マウス

1. It is well known that extracellular acidosis modulates many types of ion channels in excitable and non-excitable cells. Recently, a novel Cl- current that is activated by acidic pH has been found in rat sertoli cells. A similar current (I_<Cl.pH> was found in ventricular myocytes from mouse and guinea pig. When acidic solution was applied to the cells, I_<Cl.pH> appeared with a delay of 〜1 min, increased gradually, and reached a maximum in 〜5 min. In contrast, the current disappeared rapidly (<1 min) upon resumption of the solution with normal pH (7.4). I_<Cl.pH> was activated in a pH・dependent manner, with a half maximal activation at about pH 6.0. I_<Cl.pH> exhibited a weak time・dependent activation, the current amplitude slightly increasing during depolarizing step pulses. I・V relationship of I_<Cl.pH> showed a strong outward rectification under symmetrical [Cl-] conditions. The anion selectivity of this current was estimated to be I>Cl->Asp. Pharmacological studies showed that I … More _<Cl.pH> was inhibited by several Cl- channel blockers (DIDS, niflumic acid and gliben Cl-amide). Thus, the properties of I_<Cl.pH> differ from those of other cardiac Cl- currents (volume・regulated Cl- current, inwardly rectifying Cl- current, Ca^<2+>・activated Cl- current or CFTR current). I_<Cl.pH> may play a role in the control of the action potential duration under pathological conditions, such as ischemia-related cardiac acidosis.2. The effects of extracellular ATP on β-adrenergic activation of CFTR Cl current (I^<Cl,PKA>) were examined in guinea-pig ventricular cells. The cells were initially exposed to 0.02-1 μM isoproterenol (ISO) for 〜3 min to activate I_<Cl,PKA>, and then to 1.100 μM ATP in the presence of ISO. ATP was found to potentiate I_<Cl,PKA>, in most cells examined. In about 2/<3> of them, however, the potentiation was preceded by an inhibition, I_<Cl,PKA> changing in a biphasic manner. The initial inhibition was due to stimulation of P1-purinoceptor by ATP, since the inhibition was attenuated by the blockers of this receptor type. With 50 μM ATP, the potentiation, on average, resulted in a 1.3 fold increase of the Cl- conductance activated by ISO alone (0.02-1μM). The effects of ADP and ATPγS on I_<Cl,PKA> were similar to those of ATP, while AMP and adenosine never potentiated I_<Cl,PKA>. Thus the potentiation was attributed to a stimulation of P2-purinoceptors. PDBu (0.5 μM), an activator of PKC, facilitated I_<Cl,PKA>, and in the presence of PDBu ATP did not further potentiate I_<Cl,PKA>. When BIM (0.2 μM), an inhibitor of PKC, was present, ATP did not facilitate I_<Cl,PKA>. These findings suggested involvement of PKC in the observed ATP action. When ATP was removed in the presence of ISO, the potentiated ICl,PKA decreased (recovered) only slowly, and, if ATP was reapplied during this slowly recovering phase, the subsequent current potentiation was weak. Thus the stimulation of P_2 purinoceptors by ATP facilitates the β-adrenergic activation of I_<Cl,PKA> through PKC activation, and this potential appears to persist for several min after removal of ATP. Less

1. 众所周知，细胞外酸中毒调节可兴奋和非兴奋细胞中多种类型的离子通道。最近，在大鼠支持细胞中发现了一种由酸性 pH 值激活的新型氯电流。在小鼠和豚鼠的心室肌细胞中也发现了类似的电流（I_<Cl.pH>。当向细胞施加酸性溶液时，I_<Cl.pH>延迟约1分钟出现，逐渐增加，并在约5分钟内达到最大值。相反，当溶液恢复到正常pH（7.4）时，电流迅速消失（<1分钟）。I_<Cl.pH>在 pH 依赖性方式，在 pH 6.0 左右时具有最大激活的一半。 I_<Cl.pH>表现出弱的时间依赖性激活，在去极化阶跃脉冲期间电流幅度略有增加。 I_<Cl.pH>的I・V关系在对称[Cl-]条件下表现出强烈的向外整流。该电流的阴离子选择性估计为I>Cl->Asp。药理学研究表明我... More _<Cl.pH> 被几种 Cl-通道阻滞剂（DIDS、尼氟酸和格列本 Cl-酰胺）抑制。因此，I_<Cl.pH>的特性不同于其他心脏Cl-电流（容量·调节Cl-电流、内向整流Cl-电流、Ca^<2+>·激活Cl-电流或CFTR电流）。 I_<Cl.pH>可能起到控制作用 病理条件下的动作电位持续时间，例如缺血相关的心脏酸中毒。2．在豚鼠心室细胞中检查了细胞外 ATP 对 CFTR Cl 电流 (I^<Cl,PKA>) β-肾上腺素能激活的影响。细胞最初暴露于 0.02-1 μM 异丙肾上腺素 (ISO) 约 3 分钟以激活 I_<Cl,PKA>，然后在 ISO 存在下达到 1.100 μM ATP。在大多数检查的细胞中，发现 ATP 可以增强 I_<Cl,PKA>。然而，在它们中的大约2/ 3 中，增强之前是抑制，I_<Cl，PKA>以双相方式改变。最初的抑制是由于 P1-嘌呤受体的刺激 ATP，因为这种受体类型的阻断剂减弱了抑制作用。使用 50 μM ATP 时，单独使用 ISO (0.02-1μM) 激活的 Cl-电导平均增加 1.3 倍。 ADP和ATPγS对I_<Cl,PKA>的影响与ATP相似，而AMP和腺苷对I_<Cl,PKA>没有增强作用。因此 增强作用归因于 P2-嘌呤受体的刺激。 PDBu (0.5 μM) 是一种 PKC 激活剂，可促进 I_<Cl,PKA>，并且在 PDBu 存在下，ATP 不会进一步增强 I_<Cl,PKA>。当存在 PKC 抑制剂 BIM (0.2 μM) 时，ATP 不会促进 I_<Cl，PKA>。这些发现表明 PKC 参与了观察到的 ATP 作用。当在 ISO 存在的情况下去除 ATP 时，增强的 ICl、PKA 仅缓慢下降（恢复），并且如果在该缓慢恢复阶段重新应用 ATP，则随后的电流增强很弱。因此，ATP 对 P_2 嘌呤受体的刺激有利于 β-肾上腺素能 通过 PKC 激活 I_<Cl,PKA> 的激活，并且这种电位在去除 ATP 后似乎会持续几分钟。少

项目成果

Different intracellular polyamine concentrations underlie the difference in the inward rectifier K+ currents in atria and ventricles of the guinea‐pig heart

• DOI: 10.1113/jphysiol.2004.077677
• 发表时间: 2005-03
• 期刊: The Journal of Physiology
• 作者: Ding-Hong Yan;K. Nishimura;Kaori Yoshida;K. Nakahira;T. Ehara;K. Igarashi;K. Ishihara

Regulation of the Kir2.1 potassium channel current by intracellular pH..

细胞内 pH 值对 Kir2.1 钾通道电流的调节

• 发表时间: 2006
• 期刊: J. Physiol. Sci. 56
• 作者: Yan;D-H.
• 通讯作者: D-H.

Enhancement of ion channel formation by electrostatic interraction in-corporated in dimeric helical peptide.

通过二聚螺旋肽中的静电相互作用增强离子通道的形成。

• 发表时间: 2008
• 期刊: Peptide Science 2007
• 作者: Taira;J.
• 通讯作者: J.

Loss of regulatory volume decrease in cardiac ventricular myocytes from streptozotocin-induced type-1 diabetic mice

链脲佐菌素诱导的 1 型糖尿病小鼠心室肌细胞调节体积丧失减少

• 发表时间: 2007
• 作者: Yanamoto;S.
• 通讯作者: S.

Two Kir2.1 channel populations with different sensitivities to Mg2+ and polyamine block: a model for the cardiac strong inward rectifier K+ channel

• DOI: 10.1113/jphysiol.2004.079186
• 发表时间: 2005-03
• 期刊: The Journal of Physiology
• 作者: Ding-Hong Yan;K. Ishihara