Voltage-dependent modulation of calcium channel kinetics and its contribution to physiological functions

钙通道动力学的电压依赖性调节及其对生理功能的贡献

• 批准号: 11670038
• 负责人: NAKAYAMA Shinsuke
• 金额: $ 2.3万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11670038/
• 关键词: Calcium; Ion channels; Electrophysiology; Molecular biology; Inactivation; Persistent current; Multiple open states

In smooth muscle, it is well known that spike activities are largely due to activation of voltage-sensitive Ca^<2+> channels. Sustained Ca^<2+> influx seen during long term depolarization of the cell membrane is also considered to be through these voltage-sensitive Ca^<2+> channels. Since both phenomena are significantly suppressed by Ca^<2+> antagonists, (dihydropyridinesensitive) L-type Ca^<2+> channels seem to cover a wide range of smooth muscle behavior : from transient to persistent events.Previously, we have demonstrated the presence of multiple open states in smooth muscle L-type Ca^<2+> channels, in guinea-pig urinary bladder, taenia caeci and gastric antrum. During a large, long duration depolarization, the conformation of Ca^<2+> channels are transferred to the second open state in which these channels do not, or very slowly inactivate during depolarizaton, and deactivate very slowly upon repolarization.In 1999, using cell-attached patch clamp techniques, we mainly examined w … More hether smooth muscle Ca^<2+> channel undergoes voltage-dependent conversion of the channel conformation from normal to the second open state, even when its α_1-subunits are expressed in the plasma membrane. The answer was 'YES'. We demonstrated that α_1-subunit of cloned smooth muscle Ca^<2+> channel (α_<1C-b>) does not inactivate during large conditioning depolarization, and produced slow deactivating tail current upon repolarization of the cell membrane. These phenomena were essentially the same observed in intact smooth muscle Ca^<2+> channels.In 2000, we used whole-cell patch clamp techniques to investigate 1) the role of β-subunit in the voltage-dependent conversion of the C^<2+> channel conformation, and 2) interaction of depolarization and Ca^<2+> agonist. The experiments revealed that a smooth muscle β-subunit (β_3) decreased the ratio of the Ca^<2+> channels converted to the second open state during large depolarization, and that voltage-dependent conversion and Ca^<2+> agonistinduced mode 2 gating mechanism operated separately, causing four open states in α_1-subunit of cloned smooth muscle Ca^<2+> channel. Less

在平滑肌中，众所周知，峰电位活动主要是由于电压敏感性Ca^<2+>通道的激活。在细胞膜长期去极化过程中观察到的持续Ca^2+内流也被认为是通过这些电压敏感性Ca^2+通道。由于这两种现象都能被Ca^<2+>拮抗剂显著抑制，因此（二氢吡啶敏感的）L型Ca^<2+>通道似乎涵盖了从短暂到持续的平滑肌行为，以前，我们已经证明了在豚鼠膀胱、盲肠带和胃窦平滑肌L型Ca^<2+>通道中存在多种开放状态。在一个大的、持续时间长的去极化过程中，Ca^<2+>通道的构象被转换到第二开放状态，在这种状态下，这些通道并不去极化，或者在去极化过程中非常缓慢地去极化，并且在复极化过程中非常缓慢地失活。 ...更多信息 平滑肌Ca^<2+>通道的α_1-亚基在质膜上表达时，通道构象也会发生电压依赖性的从正常状态到第二开放状态的转变。答案是肯定的。我们证明克隆的平滑肌Ca^&lt;2+&gt;通道α_1亚基（α_<1C-b>）在大的条件性去极化过程中不发生失活，而在细胞膜复极化过程中产生慢失活尾电流。2000年，我们用全细胞膜片钳技术研究了β亚基在C^&lt;2 +&gt;通道构象电压依赖性转换中的作用，以及去极化与Ca^&lt;2+&gt;激动剂的相互作用。实验结果表明，平滑肌β亚基（β_3）降低了大去极化时Ca^&lt;2+&gt;通道转换为第二开放状态的比例，电压依赖性转换和Ca^&lt;2+&gt;激动剂诱导的模式2门控机制分别起作用，使克隆的平滑肌Ca^&lt;2+&gt;通道α_1亚基出现四种开放状态。少

项目成果

HUANG,S.-M.,et al.: "Long-term,use-dependent enhancement of impulse-induced"Neuroscience Research. 33. 239-244 (1999)

HUANG,S.-M.,et al.：“冲动诱导的长期、使用依赖性增强”神经科学研究。

SMITH,L.M., KAJIOKA,S., BRADING,A.F.& NAKAYAMA,S.: "Effects of phosphorylation-related drugs on slow Ca^<2+> tail current in guinea-pig detrusor cells."European Journal of Pharmacology. 370. 187-193 (1999)

史密斯，L.M.、梶冈，S.、布雷丁，A.F.

SMITH,L.M., ET AL.: "Effects of phosphorylation-related drugs on slow Ca^<2+> tail current in guinea-pig detrusor cells."European Journal of Pharmacology. 370. 187-193 (1999)

SMITH,L.M., 等人：“磷酸化相关药物对豚鼠逼尿肌细胞缓慢 Ca^2> 尾电流的影响。”欧洲药理学杂志。

NAKAYAMA,S., KLUGBAUER,N., KABEYA,Y., SMITH,L.M., HOFMANN,F.& KUZUYA,M.: "α_1-Subunit of smooth muscle Ca^<2+> channel preserves multiple open states induced by depolarization."Journal of Physiology. 526. 47-56 (2000)

NAKAYAMA,S.、KLUGBAUER,N.、KABEYA,Y.、SMITH,L.M.、HOFMANN,F.& KUZUYA,M.：“平滑肌 Ca^<2+> 通道的 α_1-亚基保留了去极化诱导的多种开放状态.“生理学杂志。526. 47-56 (2000)

SMITH,L.M.,et al.: "Effects of phosphorylation-related drugs on slow Ca^<2+> tail"European Journal of Pharmacology. 370. 187-193 (1999)

SMITH,L.M.,et al.：“磷酸化相关药物对慢 Ca^<2> 尾部的影响”欧洲药理学杂志。