Voltage-dependent potassium channels (KV4) are expressed in the brain and the heart where they regulate cognitive function and cardiac output. …
Continue readingCardiovascular
The Hype on the Endothelin Signaling System
Over the past two decades, research in the endothelin signaling system has been quite intensive since they are profoundly involved …
By Melanie Grably, Ph.D.
Continue reading Regional expression of cardiac ion channels and cardiac electrical activity
Important differences in electrophysiological properties have been noted between different regions of the heart. Electrophysiological heterogeneity has also been detected within different parts of a given tissue, such as the ventricular subendocardium, midmyocardium and subepicardium. Although many molecular candidates for native ionic currents have been identified, the molecular basis of most currents is not completely understood. Heterogeneity of channel protein composition might well underlie the differences observed among the properties of ionic currents or the shape of the action potential in different regions of the heart. Techniques such as immunocytochemistry, immunohistochemistry and Western blotting have played an important role in identifying tissue expression of channel proteins as well as their cellular localization. This
By Gernot Schram, M.D., Marc Pourrier, B.Sc., Peter Melnyk, B.Sc. and Stanley Nattel, M.D.
Continue reading Modulation of Heart Function by Natural Neurotoxins
Cardiac muscle cells (myocytes) are electrically excitable cells, interconnected in groups that respond to stimuli as a unit, contracting together whenever a single cell is stimulated.
Unlike the cells of other muscles and nerves, these cells show a spontaneous, intrinsic rhythm generated by specialized “pacemaker” cells, located in the sinoatrial (SA), and atrioventricular (AV) nodes of the heart. The cardiac cells also have an unusually long action potential, which can be divided into five phases (0 to 4)1,2.
By Dovrat Brass, M.Sc., B. Pharm.
Continue reading K+ Channels in Cardiomyocytes
The contribution and importance of K+ channels to the normal activity of the heart is best exemplified by disturbances in …
By Alon Meir, Ph.D.
Continue reading Voltage-Gated Ca2+ Channels in the Cardiovascular System
Voltage-gated Ca2+ channels play a pivotal role in the regulation of a wide range of cellular processes, including membrane excitability, …
By Etai Shpigel, Ph.D. and Yossi Anis, Ph.D.
Continue reading Tickling the Heart and the Nervous System with the Funny Current
Since their discovery in sinoatrial node cells and neurons in the late 1970s and early 1980s, Hyperpolarization-Activated Cyclic Nucleotide-Gated (HCN) …
By Dovrat Brass, Ph.D. and Melanie Grably, Ph.D.
Continue reading Setting the Pace with NaV1.5 Channels
SCN5A is the gene encoding NaV1.5 voltage-gated Na+ channels. These membrane proteins are responsible for the initiation and propagation of …
By Roei Levy, M.Sc. and Melanie Grably, Ph.D.
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