Analysis of mechanisms of controlling <Ca^(2+)> -channels in myocardium transplanted into the renal capsular space of the rat

大鼠肾囊腔移植心肌控制<Ca^(2)>通道的机制分析

• 批准号: 59570086
• 负责人: NISHI Katsuhide
• 金额: $ 1.09万
• 依托单位: Kumamoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1984
• 资助国家: 日本
• 起止时间: 1984 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-59570086/
• 关键词: Ion-selective microelectrode; intracellular Na activity; transplanted myocardium; 細胞内Na活性; 細胞内K活性; イオン選択性電極

1. We measured changes in membrane potential (MP), extra-and intracelllar potassium and intracellular sodium ion activities ( <a^o_k> , <a^i_k> and a <N^i_a> ) in papillary muscle of the guinea-pig heart induced by repetitive stimulation at various frequencies and periods in vitro, using double barrelled ion-selective microelecrodes. Stimulation (2-4Hz) depolarized the cells, and termination of stimulation induced hyperpolarization. <a^i_k> and a <n^i_a> (stimulated at 0.1 Hz) were 92.3 <-!+> 4.6 mM, and 7.8 <-!+> 2.0mM (mean <-!+> SD), respectively. Prolongation of the stimulation period (0.5-2 min) increased a <N^i_a> timedependently, but there was no further increase by stimulation for longer than 3 min. The increase in a <N^i_a> was dependent on stimulus-frequency. Afer termination of the stimulation, a <N^i_a> declined exponentially. <a^i_k> slightly decreased by the stimulation (3-4Hz). <a^o_k> increased during the stimulation period, and decreased below the initial level after t … More ermination of the stimulation. Results suggests that in guinea-pig papillary muscle, the contribution of an electrogenic component of Na-K pump to the hyperpolarization after stimulation would be small, since the hyperpolarization could be explained mostly by depletion of <a^o_k> induced by Na-K pump activity.2. We have developed a new model for electrophysiological studies on ischemic myocardium in situ. Pieces of ventricullar tissue(lxlmm) excised from the neonatal rat heart were transplanted into the renal capsular space of the adult rat of the pure strain F344-NSlc. Electrophysiological properies of the transplanted cells during normal circulation and during ischemia induced by ligation of the renal artery were examined in situ 7-10 days later, when the tissues were fully vascularized, by means of conventional microelectrode techniques. Transmembrane potentials varied in individual cells, ranging from -60 to -90mV. The amplitude, duration, and configuration of spontaneously occuring action potentials recorded from the transplanted cells were similar to those obtained in neonatal and adult rat myocardium. Less

1.采用双管离子选择微电极，测定了不同频率、不同时间重复刺激对豚鼠心脏乳头肌细胞膜电位、细胞内外钾离子和细胞内钠离子活度的影响。刺激(2~4赫兹)使细胞去极化，终止刺激可诱发超极化。-lt；a^i_k&gt；和a&lt；n^i_a&gt；(0.1 Hz刺激)分别为92.3&lt；-！+&gt；4.6 mm和7.8&lt；-！+&gt；2.0 mm(平均SD)。随着刺激时间的延长(0.5-2min)，a-lt；N^i_a&gt；呈时间依赖性增加，但刺激超过3min后不再进一步增加。A&lt；N^i_a&gt；的增加依赖于刺激频率。刺激终止后，a&lt；N^i_a&gt；呈指数下降。&lt；a^i_k&gt；因刺激(3-4赫兹)而略有下降。&lt；a^o_k&gt；在刺激期间升高，t…后降至初始水平以下刺激性更强。结果表明，在豚鼠乳头状肌中，Na-K泵的一个生电成分对刺激后的超极化的贡献可能很小，因为这种超极化主要是由Na-K泵活动引起的~lt；a^o_k&gt；的耗竭所致。我们建立了一种新的原位缺血心肌电生理研究模型。取新生大鼠心脏1 mm大小的脑室组织，移植到F344-NSLC纯系成年大鼠的肾囊腔内。移植细胞在正常循环和结扎肾动脉后7~10天，用常规微电极技术原位检测移植细胞的电生理特性。单个细胞的跨膜电位从-60 mV到-90 mV不等。从移植细胞记录到的自发性动作电位的幅度、时程和形态与在新生和成年大鼠心肌中获得的相似。较少

项目成果

TATSUO KANO: "External pH dependency of delayed afterepolarization in rabbit myocardium" American Jounal of Physiology. 251. H324-H330 (1986)

TATSUO KANO：“兔心肌延迟后极化的外部 pH 依赖性”美国生理学杂志。

Y.Nishizono: ADVANCES IN MYOCARDIOLOGY. 6. 383-393 (1985)

Y.Nishizono：心肌病学的进展。

TATSUO KANO: American Journal of Physiology. 251. H324-H330 (1986)

嘉野辰夫：美国生理学杂志。

西勝英: 心臓. 17. 467-476 (1985)

西胜秀：心 17. 467-476 (1985)

K. Nishi: "A model for ischemic myocardium-electrophysiological properties of myocardium transplanted tnto the renal capsular space" Shinzo. 17. 467-476 (1985)

K. Nishi：“移植到肾囊空间的心肌的缺血性心肌电生理特性的模型”Shinzo。