当前位置: X-MOL 学术Moscow Univ. Biol. Sci. Bull. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
The Effects of α 1 -Adrenoreceptors’ Activation in the Interatrial Septum of Newborn and Adult Rats
Moscow University Biological Sciences Bulletin Pub Date : 2019-11-12 , DOI: 10.3103/s009639251903009x
K. B. Pustovit , E. A. Malolina

Abstract—

Bioelectrical properties of various developing fragments of the heart undergo significant changes during pre- and postnatal ontogeny. However, the general pattern of the heart’s structure and the bioelectrical features of various parts of the “mature” heart are specifically determined in the early stages of embryogenesis. Specifically, the presence of myocardium with a phenotype, which is similar to a pacemaker, was revealed in the interatrial septum (IAS) of the mammalian heart using histological methods. However, the electrical activity in this structure remains understudied. The aim of the present study was to examine the capability of the IAS to generate action potentials spontaneously and the effects of adrenergic stimulation on the bioelectrical activity of the IAS. For this purpose, we recorded the resting and action potentials in the multicellular isolated perfused preparations of the IAS and left atrium from the rat heart at the end of day 1 and at day 60 of postnatal life using the standard microelectrode technique. We found that α1-adrenomimetic phenylephrine (PE) modified the patterns of action potentials in the samples of IAS and the atrial myocardium from the animals of both ages. In the resting samples without any electrical stimulation, PE induced the generation of action potential in the IAS but not in the atrium because of oscillations in the level of cytoplasmic calcium. Application of the inhibitor of hyperpolarization activated current (If) ZD 7288 led to a decrease in the rate of slow diastolic depolarization of action potential in the IAS pacemaker cells, a decrease in the frequency, and the appearance of train activity. Thus, in newborn and adult rats, the IAS myocardium generates spontaneous electrical activity. A necessary condition for the occurrence of pacemaker activity is adrenergic stimulation. The capability to generate spontaneous activity is probably associated with the presence of pacemaker current If in the IAS cardiomyocytes.


中文翻译:

α1-肾上腺素受体激活在新生和成年大鼠的房间隔中的作用

摘要-

在产前和产后个体发育过程中,心脏各种发育中的碎片的生物电特性都会发生重大变化。但是,心脏结构的一般模式和“成熟”心脏各部分的生物电特征是在胚胎发生的早期阶段特别确定的。具体而言,使用组织学方法在哺乳动物心脏的房间隔(IAS)中发现了具有与起搏器相似的表型的心肌。然而,在这种结构中的电活性仍然未被充分研究。本研究的目的是研究IAS自发产生动作电位的能力以及肾上腺素刺激对IAS生物电活性的影响。以此目的,我们使用标准的微电极技术记录了IAS多细胞分离灌流制剂和大鼠心脏左心房在出生后第1天结束和第60天的静息和动作电位。我们发现α1-肾上腺皮质去氧肾上腺素(PE)改变了两个年龄动物的IAS和心房心肌样品中动作电位的模式。在没有任何电刺激的静息样品中,由于胞质钙水平的振荡,PE诱导了IAS中而不是心房中动作电位的产生。激活电流(超极化的抑制剂中的应用˚F)ZD 7288导致IAS起搏器细胞中动作电位的缓慢舒张去极化率降低,频率降低和训练活动出现。因此,在新生和成年大鼠中,IAS心肌会产生自发的电活动。发生起搏器活动的必要条件是肾上腺素刺激。产生自发活动的能力可能与IAS心肌细胞中起搏器电流I f的存在有关。
更新日期:2019-11-12
down
wechat
bug