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Effects of atrial natriuretic peptide on abnormal automaticity of diseased human atrial muscles.

心房钠尿肽对患病人类心房肌肉异常自律性的影响。

基本信息

批准号：
01570497
负责人：
IMANISHI Sunao
金额：
$ 1.34万
依托单位：
Oita Medical 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：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01570497/
关键词：
human atrial muscles abnormal automaticity intracellular K^+ activity intracellular Na^+ activity single human artial cells acetylcholine nicorandil atrial natriuretic peptide 病的ヒト心房筋 Triggered Activity 単離ヒト心房細胞パッチクランプ

项目摘要

A human atrial trabecula(0.8xl. 5mm)was dissected from a small piece of right atrial appendage excised from patients undergoing cardiac surgery. We first attempted to elucidate the ionic mechanisms for the low resting membrane potential(Vm)of human atrial preparations using double-barreled K^+- and Na^+-sensitive microelectrodes. Because various types of abnormal automaticities observed at a rate of about 70% in the ppecimens may be mainly caused by partial depolarizations of Vm. The intracellular K^+ activity(a^i_averaged 99.7<plus-minus>1.3mM(n=33), intracellular Na^+ activity(a^i_, 6.9<plus-minus>1.7mM(n=9)and Vm, 43.6<plus-minus>3.2(n=42). These findings suggest that the depolarization of Vm is neither due to a decrease in a^i_ nor an increase in a^i_ but probably due to a decrease in K^+ permeability for the membrane. We secondly examined the effects of atrial natriuretic peptide(ANP)on action potential characteristics and contractile tension of the human preparations. However, we found no significant effect of ANP on those parameters. So we intended to test the effects of ANP on the ionic current in single human atrial myocytes using whole cell voltage-clamp technique. However, there was only one isolated cell tolerable to do experiment among 31 human atrial tissues undergone cell-isolation procedures. Therefore, we could not obtain available informations about electrophysiologic effects of ANP on single human atrial cell, though we observed electrophysiologically reasonable actions of acetylcholine and nicorandil on it.

人心房小梁（0.8xl. 5mm）从接受心脏手术的患者切除的一小块右心耳上剥离。我们首先尝试使用双管K^+和Na^+敏感微电极来阐明人心房制备物的低静息膜电位（Vm）的离子机制。因为在病人中观察到的约70%的各种异常自律性可能主要由Vm的部分去极化引起。细胞内K^+活性（a^i）平均为99.7 <plus-minus>± 1.3mM（n=33），Na^+活性（a^i）平均为6.9 <plus-minus>± 1.7mM（n=9），Vm平均为43.6 <plus-minus>± 3.2（n=42）。这些结果表明，Vm的去极化既不是由于a^i_的减小，也不是由于a^i_的增大，而可能是由于膜的K^+渗透性的减小。其次，我们研究了心房钠尿肽（ANP）对人体标本动作电位特性和收缩张力的影响。然而，我们发现ANP对这些参数没有显着影响。因此，本实验拟采用全细胞电压钳技术研究心钠素对单个人心房肌细胞离子电流的影响。然而，在31例进行细胞分离的人心房组织中，只有1例分离的细胞可耐受进行实验。因此，尽管我们观察到了乙酰胆碱和尼可地尔对单个人心房肌细胞的电生理作用，但我们无法获得关于ANP对单个人心房肌细胞的电生理作用的可用信息。