Regulation of the cardiac delayed rectifier K^+ channel by membrane phosphoinositides

膜磷酸肌醇对心脏延迟整流 K^ 通道的调节

• 批准号: 13670042
• 负责人: MATSUURA Hiroshi
• 金额: $ 1.92万
• 依托单位: Shiga University of Medical Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13670042/
• 关键词: delayed rectifier K^+ current; I_<ks>; phosphatidylinositol 4, 5-bisphosphate; PtdIns(4, 5)P_2; wortmannin; anti-PtdIns(4, 5)P_2, monoclonal antibodies; neomycin; electrostatic interactions; パッチクランプ法; イノシトールリン脂質; ホスファチジルイノシトール4.5二リン酸; 抗体; 遅延整流

Regulation of the slowly activating component of delayed rectifier K^+ current (I_<ks>) by the membrane phospholipid phosphatidylinositol 4, 5-bisphosphate (PtdIns(4, 5)P_2) was examined in guinea-pig atrial cells using whole-cell patch-clamp method. Intracellular application of 50 μM wortmannin through a recording pipette evoked progressive increase in I_<ks> over a 10-15 min to 208.5±14.6% (n = 9) of initial magnitude obtained shortly after rupture of the patch membrane, when assessed by measuring the amplitude of tail current elicited upon return to a holding potential of -50 mV following a 2-s depolarization to +30 mV. Intracellular application of anti-PtdIns(4, 5)P_2 monoclonal antibodies also increased the amplitude of I_<ks> tail current to 198.4±19.9% (n = 5). In contrast, intracellular loading of atrial cells with exogenous PtdIns(4, 5)P_2 (100μM) produced a marked decrease in the amplitude of I_<ks> tail current to 44.8±8.2% (n = 5). These results strongly suggest that endogenous membrane PtdIns(4, 5)P_2 produces a potent inhibitory action on I_<ks> channels. Intracellular application of neomycin (50 μM) or aluminum (50 μM) evoked an increase in the amplitude of I_<ks> tail current to 161.0±13.5% (n = 4) and 150.0±8.2% (n = 4), respectively, which suggests that I_<ks> channel is inhibited by membrane PtdIns(4, 5)P_2 through electrostatic interactions with negatively charged head group on PtdIns(4, 5)P_2. Enhancement of I_<ks> by P2Y receptor stimulation with 50 μM ATP was almost totally abolished by exogenously applied PtdIns(4, 5)P_2. This result suggests that depletion of membrane PtdIns(4, 5)P_2 is primarily involved in an enhancement of I_<ks> evoked by stimulation of P2Y receptor in guinea-pig atrial cells.

使用全细胞膜片钳方法在豚鼠心房细胞中检查了膜磷脂磷脂酰肌醇 4, 5-二磷酸 (PtdIns(4, 5)P_2) 对延迟整流 K^+ 电流 (I_<ks>) 的缓慢激活成分的调节。通过记录移液管在细胞内应用 50 μM 渥曼青霉素，在 10-15 分钟内引起 I_<ks> 逐渐增加，达到膜片破裂后不久获得的初始幅度的 208.5±14.6% (n = 9)，通过测量在 2 秒去极化至 +30 mV 后返回到 -50 mV 保持电位时引起的尾电流幅度进行评估。细胞内应用抗PtdIns(4, 5)P_2单克隆抗体也将I_<ks>尾电流的幅度增加至198.4±19.9%(n = 5)。相反，用外源性PtdIns(4, 5)P_2 (100μM)对心房细胞进行细胞内负荷，导致I_<ks>尾电流的幅度显着降低至44.8±8.2% (n = 5)。这些结果强烈表明内源性膜 PtdIns(4, 5)P_2 对 I_<ks> 通道产生有效的抑制作用。细胞内应用新霉素 (50 μM) 或铝 (50 μM) 引起 I_<ks> 尾电流幅度分别增加至 161.0±13.5% (n = 4) 和 150.0±8.2% (n = 4)，这表明 I_<ks> 通道通过静电相互作用被膜 PtdIns(4, 5)P_2 抑制 PtdIns(4, 5)P_2 上带有带负电的头基。 50 μM ATP 刺激 P2Y 受体对 I_<ks> 的增强几乎被外源应用的 PtdIns(4, 5)P_2 完全消除。该结果表明，膜PtdIns(4, 5)P_2的消耗主要涉及通过刺激豚鼠心房细胞中的P2Y受体引起的I_<ks>增强。

项目成果

Matsuura,H., Ehara,T., Ding,W.G., Omatsu-Kanbe,M., Isono,T.: "Rapidly and slowly activating components of delayed rectifier K^+ current in guinea-pig sino-atrial node pacemaker cells"J Physiol. 540. 815-830 (2002)

Matsuura,H.、Ehara,T.、Ding,W.G.、Omatsu-Kanbe,M.、Isono,T.：“豚鼠窦房结起搏细胞中延迟整流 K^ 电流的快速和缓慢激活成分”J

Shimizu, K.: "Potentiation of slow component of delayed rectifier K^+ current by cyclic GMP via two distinct mechanisms : inhibition of phosphodiesterase 3 and activation of protein kinase G"Br J Pharmacol. 137. 127-137 (2002)

Shimizu, K.：“环 GMP 通过两种不同的机制增强延迟整流器 K^ 电流的慢速成分：抑制磷酸二酯酶 3 和激活蛋白激酶 G”Br J Pharmacol。

Omatsu-Kanbe,M., Isono,T., Matsuura,H.: "Multiple P2 receptors contribute to a transient increase in intracellular Ca^<2+> concentration in ATP-stimulated rat brown adipocytes"Exp Physiol. 87. 643-652 (2002)

Omatsu-Kanbe,M.、Isono,T.、Matsuura,H.：“多种 P2 受体有助于 ATP 刺激的大鼠棕色脂肪细胞中细胞内 Ca^2 浓度的瞬时增加”Exp Physiol。

Ding, W.G.: "Blocking action of chromanol 293B on the slow component of delayed rectifier K^+ current in guinea-pig sino-atrial node cells"Br J Pharmacol. 137. 253-262 (2002)

Ding，W.G.：“色醇 293B 对豚鼠窦房结细胞中延迟整流 K 电流慢分量的阻断作用”Br J Pharmacol。

Omatsu-Kanbe, M.: "Multiple P2 receptors contribute to a transient increase in intracellular Ca^<2+> concentration in ATP-stimulated rat brown adipocytes"Exp Physiol. 87. 643-652 (2002)

Omatsu-Kanbe，M.：“多个P2受体有助于ATP刺激的大鼠棕色脂肪细胞中细胞内Ca 2+ 浓度的短暂增加”Exp Physiol。