Effects of ACh and IJPs on the AV Valve and the Ventricle of Dolabella auricularia
Effects of ACh and IJPs on the AV Valve and the Ventricle of Dolabella auricularia
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ACh 和 IJP 对 AV 瓣和心室的影响
DOI：
10.1093/icb/19.1.129
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
K. Kuwasawa
中科院分区：
文献类型：
--
作者：
K. Kuwasawa
电镜观察和电生理观察表明，耳室瓣心肌组织与Dolabella心室心肌组织存在一定差异。
心室中的肌细胞比耳室瓣中的肌细胞排列更整齐，其中肌细胞的排列在许多方向上，表明交织结构。
心室的心肌细胞比房室瓣的心肌细胞有更多致密的肌原纤维和更明显的肌节。
当这两个部位被一起切开时，可以注意到，在心室中出现动作电位之前，耳室瓣几乎总是激发动作电位。因此，房室瓣的起搏点支配心室的起搏点。
乙酰胆碱通常引起心室去极化和房室瓣超极化，对房室瓣的作用与抑制性交界电位相似。
两个部位的心肌细胞膜电导均被乙酰胆碱增加。这可能是由于这两个部位的钠和钾渗透性增加所致。因此，两个部位之间乙酰胆碱作用的差异，即心室去极化和耳室瓣超极化的差异，可能是由于两个部位之间初始膜电位的差异以及钠和钾电导率增加的比率的差异造成的。
结果表明，有一些网站之间的功能分化。这表明，即使心脏具有弥漫性肌源性，在Dolabella auricularia中也已经开发了传导系统。
Some differences exist between myocardial tissue of the auriculo-ventricular valve and the ventricle of Dolabella , which have been revealed by means of electron microscopic and electrophysiological investigations.
The muscle cells in the ventricle are more neatly arranged than those in the auriculoventricular valve, in which the alignments of the muscle cells run in many directions, indicating an interwoven structure.
Myocardial cells of the ventricle have more condensed myofibrils and more apparent sarcomeres than those of the auriculo-ventricular valve.
When both the sites are dissected out together, it is noticeable that the auriculo-ventricular valve almost always fires an action potential before an action potential appears in the ventricle. Thus the pacemaker of the auriculo-ventricular valve dominates that of the ventricle.
Acetylcholine usually causes depolarization in the ventricle and hyperpolarization in the auriculo-ventricular valve and has similar actions on the auriculo-ventricular valve as do inhibitory junctional potentials.
Membrane conductance of the myocardium in both sites is increased by acetylcholine. This possibly resultsfrom increase of sodium and potassium permeability in both sites. Thus, the difference in effects of acetylcholine between the two sites, depolarization in the ventricle and hyperpolarization in the auriculo-ventricular valve, might result from the difference in the initial membrane potential and in the ratio of increasedconductance for sodium and potassium between the sites.
Results show that there is some functional differentiation between the sites. It indicates that even though the heart has a diffuse myogenic nature, a conduction system has been developed in Dolabella auricularia .