Investigation of pathophysiological properties of ion channels on cardiac sarcoplasmic reticulum.

心脏肌浆网离子通道病理生理特性的研究。

• 批准号: 05044151
• 负责人: HIRAOKA Masayasu
• 金额: $ 3.84万
• 依托单位: Tokyo Medical and Dental University, Medical Research Institute
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05044151/
• 关键词: Ryanodine receptor Ca^<2+> release channel; sarcoplasmic reticulum; artificial lipid bilayr; Cl-channel; Cl-チャネル; リャノジン受容体チャネル; 小胞体; 隣酸化

(1) Investigation of regulatory mechanism of ryanodine receptor Ca^<2+> release channel. To investigate the regulatory mechanisms of ryanodine receptor Ca^<2+> release channel in cardiac sarcoplasmic reticulum (SR), we purified the SR membrane from pig hearts. These procedures were done in Dr.Coronado's lab at University of Wisconsin. The ryanodine receptors were incorporated into the artificial lipid bilayr and the channel activities were recorded by voltage clamp technique. Dr.Kawano and Dr.Hiraoka visited Dr.Coronado's lab to study and to discuss the procedure of purification of ryanodine receptors from pigs and bovine hearts. By using these preparations, we could record channel activities of ryanodine receptor. In this study we investigated Mg^<2+> effects on this channel and found that Mg^<2+> blocked the channel openings with diverse mechanisms. Namely, (1) Mg^<2+> reduced channel openings by competing with Ca^<2+> at the Ca^<2+> binding activating site of the channel and (2) by … More reducing the channel conductance.Thus, we showed the detail regulatory mechanisms of Ca^<2+> release from SR by Mg^<2+>.(2) Investigation of anion selectivity of a chloride channel in the porcine cardiac sarcoplasmic reticulum. We have reported that Cl-channel are present on cardiac sarcoplasmic reticulum which is activated by cyclic AMP dependent phosphorylation. In this study we examined the ion selectivity of this channel and compare the pore properties of this channel to those of other Cl-channels. Permeability ration calculated by Goldman-Hodgikin-Katz equation revealed the anion permeability sequence as Br->Cl->I->NO_3->F-. Those results were comparable to those of cystic fibrosis transmembrane regulator (CFTR) and the cardiac Cl-channel on the sarcolemma. The biophysical properties of this Cl-channel are very similar to those of the CFTR,suggesting the pore with a moderately high affinity site for anions. Therefor we speculate that cardiac SR Cl-channel may belong to the same family of Cl-channel as CFTR.Dr.Coronado found chloride-induced Ca^<2+> release from sarcoplasmic reticulum. Therefore, we had good discussions about the relationships between these channels on SR and Cl-channel. We could show the new signal tansduction pathway between channels on sarcolemma and those on SR,because of collaboration with Dr.Coronado. Less

(1)兰尼碱受体Ca^2+释放通道调控机制研究。为了研究心脏肌浆网(SR)中兰尼碱受体Ca^2+释放通道的调节机制，我们纯化了猪心脏的SR膜。这些程序是在威斯康星大学科罗纳多博士的实验室中完成的。将兰尼碱受体掺入人工脂质双层中，并通过电压钳技术记录通道活性。 Kawano博士和Hiraoka博士参观了Coronado博士的实验室，对从猪和牛心脏中纯化兰尼碱受体的过程进行了研究和讨论。通过使用这些制剂，我们可以记录兰尼碱受体的通道活性。在本研究中，我们研究了 Mg^<2+> 对该通道的影响，发现 Mg^<2+> 通过不同的机制阻塞通道开口。即，(1) Mg^<2+> 通过在通道的 Ca^<2+> 结合激活位点与 Ca^<2+> 竞争来减少通道开放，(2) 通过降低通道电导。因此，我们展示了 Mg^<2+> 从 SR 释放 Ca^<2+> 的详细调节机制。(2) 猪心脏氯离子通道阴离子选择性的研究 肌浆网。我们已经报道，Cl-通道存在于心脏肌浆网上，其被环AMP依赖性磷酸化激活。在本研究中，我们检查了该通道的离子选择性，并将该通道的孔隙特性与其他 Cl 通道的孔隙特性进行了比较。通过Goldman-Hodgikin-Katz方程计算的渗透率比显示阴离子渗透率顺序为Br->Cl->I->NO_3->F-。这些结果与囊性纤维化跨膜调节器 (CFTR) 和肌膜上的心脏 Cl 通道的结果相当。该 Cl 通道的生物物理特性与 CFTR 的生物物理特性非常相似，表明该孔对阴离子具有中等高的亲和力位点。因此我们推测心脏SR Cl通道可能与CFTR属于同一Cl通道家族。Coronado博士发现氯化物诱导肌浆网Ca 2+ 释放。因此，我们对SR和Cl通道上这些通道之间的关系进行了很好的讨论。由于与 Coronado 博士的合作，我们可以展示肌膜通道和 SR 通道之间的新信号传导途径。较少的

项目成果

S.Kawano: "Direct effects of verapamil on the ryanodine receptor Ca^<2+> -release channel of sarcoplasmic retirulum." Jpn.Circ.J.58. 458 (1994)

S.Kawano：“维拉帕米对肌浆网的兰尼碱受体 Ca^2 -释放通道的直接影响。”

Kawano,S.: "Protein kinase A-activated chloride channel is inhibited by the Ca^<2+>-calmoduline complex in cardiac sarcoplsmic reticulum." Circulation Research. 73. 751-757 (1993)

Kawano,S.：“蛋白质激酶A激活的氯离子通道被心脏肌质网中的Ca^2-钙调蛋白复合物抑制。”

S.Kawano: "Activation mechanism of the Ca^<2+> sensitive transient outward current by intracellular Ca^<2+> in rabbit ventricular myocyte." 44. S75- (1994)

S.Kawano：“兔心室肌细胞内Ca^2>对Ca^2敏感瞬时外向电流的激活机制”。

S.Kawano: "Protein kinase A-activated chloride channel is inhibited by Ca^<2+> calmodulin complex in cardiac sarcoplasmic reticulum." Circ.Res.73. 751-757 (1993)

S.Kawano：“蛋白质激酶A激活的氯离子通道被心脏肌浆网中的Ca 2+ 钙调蛋白复合物抑制。”

S.Kawano: "Activation mechanism of the Ca^<2+> sensitive transient outward current by intracellular Ca^<2+> in rabbit ventricular myocytes." Jpn.J.Physiol.44. S75 (1994)

S.Kawano：“兔心室肌细胞内Ca^2>对Ca^2敏感瞬时外向电流的激活机制。”