An electrophysiological study on miniature Ca relelase from the sarcoplasmic reticulum in cardiac myocytes.

心肌细胞肌浆网微型 Ca 释放酶的电生理学研究。

• 批准号: 63570040
• 负责人: EHARA Tsuguhisa
• 金额: $ 1.41万
• 依托单位: Saga Medical School (1989)Kyushu University (1988)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63570040/
• 关键词: Ca^<2+>-mediated ion channel; sarcoplasmic reticulum; whole cell recording; caffeine; Ca release; 心室筋細胞

Abstract. In order to examine the effects of increased intracellular Ca^<2+> level on the membrane electrical activity, caffeine, the agent which facilitates Ca^<2+> release from the sarcoplasmic reticulum, was applied to single ventricular cells of the guinea-pig, under condition of the whole cell recording. Caffeine (10 - 25 mM) induced a burst of pulse-like small inward currents. The amplitude of the pulse-like inward currents, which appeared to have a unit magnitude, decreased as the membrane was depolarized, and the reversal potential was estimated to be near 0 mV. Thus, the responsible ion channel may have a unit conductance of 250 - 300 pS. The pulse-like activity persisted when external NaCl was replaced with LiCl, but it disappeared in Tris-Cl solution. Large depolarizations producing sustained cell shortening or intracellular Ca^<2+>-injection enhanced the pulse-like events, suggesting a role of intracellular Ca^<2+> in this phenomenon. Ni^<2+> ions partially inhibited the pulse-like activity. Thus, the ventricular cells appeared to have Ca^<2+>-mediated cation channels with a large conductance, but possible involvement of a specific action of caffeine in the channel activation was not excluded.

抽象的。为了检查细胞内Ca ^ 2+ 水平增加对膜电活动的影响，将促进Ca ^ 2+ 从肌浆网释放的试剂咖啡因应用于几内亚的单心室细胞。猪，全细胞记录条件下。咖啡因 (10 - 25 mM) 会引发一阵脉冲状的小内向电流。脉冲状内向电流的幅度似乎具有单位幅度，随着膜去极化而减小，并且反转电位估计接近 0 mV。因此，负责的离子通道可以具有250-300 pS的单位电导。当外部 NaCl 被 LiCl 取代时，脉冲状活性仍然存在，但在 Tris-Cl 溶液中消失。产生持续细胞缩短或细胞内Ca 2+ 注射的大去极化增强了脉冲状事件，表明细胞内Ca 2+ 在该现象中的作用。 Ni 2+ 离子部分抑制脉冲样活性。因此，心室细胞似乎具有具有大电导的Ca 2+ 介导的阳离子通道，但不排除咖啡因的特定作用参与通道激活的可能。

项目成果

Ehara, T.: J. Physiol. (1989)

Ehara, T.：J. Physiol。

Ehara,T.: "Measurement of reversal potential of Na/Ca exchange current in single ventricular cells of guinea-pig." J.Physiol.410. 227-249 (1989)

Ehara,T.：“测量豚鼠单心室细胞中 Na/Ca 交换电流的反转电位。”

Ehara, T.: J. Physiol.403. 117-133 (1988)

Ehara，T.：J.Physiol.403。

Ehara,T.: "Anion channels activated by adrenaline in cardiac myocytes." Nature. (1990)

Ehara,T.：“心肌细胞中肾上腺素激活的阴离子通道。”

Matsuoka, S.: "Reversal potential of the Na-Ca exchange current in the cardiac myocyte of the guinea-pig." Biomed. Res. Suppl., 2: 149-152, 1989.

Matsuoka, S.：“豚鼠心肌细胞中 Na-Ca 交换电流的逆转电位。”