The Ionic Basis of Electrical Activity in Embryonic Cardiac Muscle
نویسندگان
چکیده
The intracellular sodium concentration reported for young, embryonic chick hearts is extremely high and decreases progressively throughout the embryonic period, reaching a value of 43 mM immediately before hatching. This observation suggested that the ionic basis for excitation in embryonic chick heart may differ from that responsible for electrical activity of the adult organ. This hypothesis was tested by recording transmembrane resting and action potentials on hearts isolated from 6-day and 19-day chick embryos and varying the extracellular sodium and potassium concentrations. The results show that for both young and old embryonic cardiac cells the resting potential depends primarily on the extracellular potassium concentration and the amplitude and rate of rise of the action potential depend primarily on the extracellular sodium concentration.
منابع مشابه
The Electrical Activity of the Heart
T heart beats in the absence of any nervous connections because the electrical (pacemaker) activity that generates the heartbeat resides within the cardiac muscle. After initiation, the electrical activity spreads throughout the heart, reaching every cardiac cell rapidly with the correct timing. This enables coordinated contraction of individual cells. The electrical activity of cardiac cells d...
متن کاملIdentification of Two Main Independent Components of Fibrillating Heart Muscle
Fibrillation is a hazardous phenomenon in cardiac muscle and so any new work towards the understanding of this process is important to the development of new methods in diagnosis and therapy. In this work we have used surface and intra cardiac ECGs of patients with chronic atrial fibrillation (AF). By means of the blind source separation (BSS) algorithm, which is a well-known method in signal p...
متن کاملAn ionic model for rhythmic activity in small clusters of embryonic chick ventricular cells.
We recorded transmembrane potential in whole cell recording mode from small clusters (2-4 cells) of spontaneously beating 7-day embryonic chick ventricular cells after 1-3 days in culture and investigated effects of the blockers D-600, diltiazem, almokalant, and Ba2+. Electrical activity in small clusters is very different from that in reaggregates of several hundred embryonic chick ventricular...
متن کاملP-74: Effect of Fndc5 Overexpression onCardiac Differentiation Rate of mESCs
Background: Fibronectin type III domain-containing 5 proteins (Fndc5), an exercise hormone, formerly known as peroxisomal protein that was cloned in 2002. Transcript profile analysis of Fndc5 revealed high degree of expression in heart, skeletal muscle and brain. Our recent studies indicated a significant increase (approximately 10 folds) in mRNA level of Fndc5 when mouse embryonic stem cells w...
متن کاملSimple experiments to understand the ionic origins and characteristics of the ventricular cardiac action potential.
Electrophysiological experiments are helpful for students to understand the role of electrical activity in heart function. Papillary muscle, which belongs to the ventricle, offers the advantage of being easily studied using glass microelectrodes. In addition, there is commercially available software that simulates ventricular electrical activity and can help overcome some difficulties, such as ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The Journal of General Physiology
دوره 52 شماره
صفحات -
تاریخ انتشار 1968