Cellular Electrophysiology

Cellular electrophysiology has been revolutionized by the introduction of patch clamp techniques. The patch clamp records current from a small patch of the cell membrane which has been sucked into a glass pipette. The membrane patch, a few micons in diameter, is attached to the glass by a seal which is electrically, diffusionally and mechanically tight. Because of the tight electrical seal, the noise level is low enough to record the activity of single ion channels over a time scale extending from 10μs to days. However, although the patch technique is over ten years old, the patch structure is unknown. The patch is inside a glass pipette where it has been impossible to see with standard electron microscopes. We show here that at 1 Mev the glass pipette is transparent and the membrane within can be seen with a resolution of about 30 A.

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Endurance exercise training normalizes repolarization and calcium-handling abnormalities, preventing ventricular fibrillation in a model of sudden cardiac death

Journal of Applied Physiology ◽

10.1152/japplphysiol.00175.2012 ◽

2012 ◽

Vol 113 (11) ◽

pp. 1772-1783 ◽

Cited By ~ 15

Author(s):

Ingrid M. Bonilla ◽

Andriy E. Belevych ◽

Arun Sridhar ◽

Yoshinori Nishijima ◽

Hsiang-Ting Ho ◽

...

Keyword(s):

Sudden Cardiac Death ◽

Exercise Training ◽

Endurance Exercise ◽

Cardiac Death ◽

Outward Current ◽

Calcium Handling ◽

Transient Outward Current ◽

Cellular Electrophysiology ◽

Endurance Exercise Training

The risk of sudden cardiac death is increased following myocardial infarction. Exercise training reduces arrhythmia susceptibility, but the mechanism is unknown. We used a canine model of sudden cardiac death (healed infarction, with ventricular tachyarrhythmias induced by an exercise plus ischemia test, VF+); we previously reported that endurance exercise training was antiarrhythmic in this model (Billman GE. Am J Physiol Heart Circ Physiol 297: H1171–H1193, 2009). A total of 41 VF+ animals were studied, after random assignment to 10 wk of endurance exercise training (EET; n = 21) or a matched sedentary period ( n = 20). Following (>1 wk) the final attempted arrhythmia induction, isolated myocytes were used to test the hypotheses that the endurance exercise-induced antiarrhythmic effects resulted from normalization of cellular electrophysiology and/or normalization of calcium handling. EET prevented VF and shortened in vivo repolarization ( P < 0.05). EET normalized action potential duration and variability compared with the sedentary group. EET resulted in a further decrement in transient outward current compared with the sedentary VF+ group ( P < 0.05). Sedentary VF+ dogs had a significant reduction in repolarizing K+ current, which was restored by exercise training ( P < 0.05). Compared with controls, myocytes from the sedentary VF+ group displayed calcium alternans, increased calcium spark frequency, and increased phosphorylation of S2814 on ryanodine receptor 2. These abnormalities in intracellular calcium handling were attenuated by exercise training ( P < 0.05). Exercise training prevented ischemically induced VF, in association with a combination of beneficial effects on cellular electrophysiology and calcium handling.

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Edward E. Carmeliet, MD, PhD (January 4, 1930–April 5, 2021): A pioneer in cardiac cellular electrophysiology

Heart Rhythm ◽

10.1016/j.hrthm.2021.06.1173 ◽

2021 ◽

Vol 18 (8) ◽

pp. 1460-1461

Author(s):

André G. Kléber ◽

Michael R. Rosen ◽

Michiel J. Janse ◽

Denis Noble

Keyword(s):

Cellular Electrophysiology

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Systematic characterization of the ionic basis of rabbit cellular electrophysiology using two ventricular models

Progress in Biophysics and Molecular Biology ◽

10.1016/j.pbiomolbio.2011.06.012 ◽

2011 ◽

Vol 107 (1) ◽

pp. 60-73 ◽

Cited By ~ 28

Author(s):

Lucía Romero ◽

Beatriz Carbonell ◽

Beatriz Trenor ◽

Blanca Rodríguez ◽

Javier Saiz ◽

...

Keyword(s):

Cellular Electrophysiology ◽

Ionic Basis

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