Cardiac purkinje cells in culture

1984 ◽  
Vol 16 ◽  
pp. iv-iv
Author(s):  
E CANALE ◽  
J CAMPBELL ◽  
G CAMPBELL
1980 ◽  
Vol 238 (4) ◽  
pp. H561-H568
Author(s):  
S. R. Houser ◽  
A. R. Freeman

Volumetric properties of canine cardiac Purkinje fibers were examined. Purkinje cells were superfused with anisosmolar solutions, and changes in extracellular space and relative cell volume were determined. The relationship between cellular volume and the osmolarity of the bathing medium was shown to be linear except in solutions of very low osmolarity. A linear regression line crossed the volume axis at 38%, suggesting an osmometric dead space of 38% and correspondingly an osmometric compartment comprising about 62% of the cell interior. To determine the volumetric properties of the "electrophysiological compartment," Purkinje cells were impaled with voltage-sensitive microelectrodes, and cellular resting potentials were recorded. When log K was plotted against resting potential (Em) in preparations bathed in normal and hyperosmotic solutions, it was shown that Em was increased in hyperosmotic solutions (13.5 and 21 mV in 600 and 850 mosM solutions, respectively). Calculations using the Nernst equation showed that the compartment containing the intracellular K involved in membrane electrical events behaves as a near-perfect osmometer in hyperosmotic solutions. Changes in the osmometric compartment were well correlated with K changes in the electrophysiological compartment, thus suggesting that the K is homogeneously distributed intracellularly.


Stem Cells ◽  
2015 ◽  
Vol 33 (4) ◽  
pp. 1102-1112 ◽  
Author(s):  
Karen Maass ◽  
Akshay Shekhar ◽  
Jia Lu ◽  
Guoxin Kang ◽  
Fiona See ◽  
...  

2004 ◽  
Vol 61 (9) ◽  
pp. 1106-1113 ◽  
Author(s):  
A. O. Verkerk ◽  
R. Wilders ◽  
J. H. Ravesloot

2002 ◽  
Vol 283 (6) ◽  
pp. H2495-H2503 ◽  
Author(s):  
Wei Han ◽  
Liming Zhang ◽  
Gernot Schram ◽  
Stanley Nattel

Cardiac Purkinje fibers play an important role in cardiac arrhythmias, but no information is available about ionic currents in human cardiac Purkinje cells (PCs). PCs and midmyocardial ventricular myocytes (VMs) were isolated from explanted human hearts. K+ currents were evaluated at 37°C with whole cell patch clamp. PCs had clear inward rectifier K+current ( I K1), with a density not significantly different from VMs between −110 and −20 mV. A Cs+-sensitive, time-dependent hyperpolarization-activated current was measurable negative to −60 mV. Transient outward current ( I to) density was smaller, but end pulse sustained current ( I sus) was larger, in PCs vs. VMs. I to recovery was substantially slower in PCs, leading to strong frequency dependence. Unlike VM I to, which was unaffected by 10 mM tetraethylammonium, Purkinje I to was strongly inhibited by tetraethylammonium, and Purkinje I to was 10-fold more sensitive to 4-aminopyridine than VM. PC I sus was also reduced strongly by 10 mM tetraethylammonium. In conclusion, human PCs demonstrate a prominent I K1, a time-dependent hyperpolarization-activated current, and an I towith pharmacological sensitivity and recovery kinetics different from those in the atrium or ventricle and compatible with a different molecular basis.


1990 ◽  
Vol 95 (3) ◽  
pp. 411-437 ◽  
Author(s):  
B E Scanley ◽  
D A Hanck ◽  
T Chay ◽  
H A Fozzard

Single sodium channel events were recorded from cell-attached patches on single canine cardiac Purkinje cells at 10-13 degrees C. Data from four patches containing two to four channels and one patch with one channel were selected for quantitative analysis. The channels showed prominent reopening behavior at voltages near threshold, and the number of reopenings declined steeply with depolarization. Mean channel open time was a biphasic function of voltage with the maximum value (1-1.5 ms) occurring between -50 and -40 mV and lower values at more and at less hyperpolarized levels. Inactivation without opening was also prominent near threshold, and this occurrence also declined with depolarization. The waiting time distributions and the probability of being open showed voltage and time dependence as expected from whole-cell current studies. The results were analyzed in terms of a five-state Markovian kinetic model using both histogram analysis and a maximum likelihood method to estimate kinetic parameters. The kinetic parameters of the model fits were similar to those of GH3 pituitary cells (Horn, R., and C. A. Vandenberg. 1984. Journal of General Physiology. 84:505-534) and N1E115 neuroblastoma cells (Aldrich, R. W., and C. F. Stevens. Journal of Neuroscience. 7:418-431). Both histogram and maximum likelihood analysis implied that much of the voltage dependence of cardiac Na current is in its activation behavior, with inactivation showing modest voltage dependence.


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