scholarly journals Kinetics and rectification of the slow inward current in the rabbit sinoatrial node cell.

1981 ◽  
Vol 31 (4) ◽  
pp. 491-500 ◽  
Author(s):  
Akinori NOMA ◽  
Hiroshi KOTAKE ◽  
Shinichiro KOKUBUN ◽  
Hiroshi IRISAWA
1977 ◽  
Vol 372 (1) ◽  
pp. 43-51 ◽  
Author(s):  
A. Noma ◽  
K. Yanagihara ◽  
H. Irisawa

1987 ◽  
Vol 136 (1) ◽  
pp. 113-117 ◽  
Author(s):  
Hiroshi Kotake ◽  
Makoto Saitoh ◽  
Kazuhide Ogino ◽  
Yasutaka Kurata ◽  
Akira Ohtahara ◽  
...  

1986 ◽  
Vol 250 (2) ◽  
pp. H325-H329 ◽  
Author(s):  
R. D. Nathan

Previous investigations employing multicellular nodal preparations (i.e., mixtures of dominant and subsidiary pacemaker cells) have suggested that the fast transient inward sodium current (iNa) either is not present in dominant pacemaker cells or is present but inactivated at the depolarized take-off potentials that these cells exhibit. In the present study, this question was resolved by voltage clamp analysis of single pacemaker cells isolated from the sinoatrial node and maintained in vitro for 1-3 days. Two types of cells, each with a different morphology, exhibited two modes of electrophysiological behavior. Type I cells (presumably dominant pacemakers) displayed only a tetrodotoxin (TTX)-resistant (but cadmium-sensitive) slow inward current, whereas type II cells (presumably subsidiary pacemakers) exhibited two components of inward current, a TTX-sensitive, fast transient inward current and a TTX-resistant (but cadmium-sensitive) slow inward current. Three other voltage-gated currents, 1) a slowly developing inward current activated by hyperpolarization (if, ih, delta ip), 2) a transient outward current activated by strong depolarization (ito, iA), and 3) a delayed outward current, were recorded in both types of pacemaker cells.


1994 ◽  
Vol 266 (3) ◽  
pp. C832-C852 ◽  
Author(s):  
S. S. Demir ◽  
J. W. Clark ◽  
C. R. Murphey ◽  
W. R. Giles

A mathematical model for the electrophysiological responses of a rabbit sinoatrial node cell that is based on whole cell recordings from enzymatically isolated single pacemaker cells at 37 degrees C has been developed. The ion channels, Na(+)-K+ and Ca2+ pumps, and Na(+)-Ca2+ exchanger in the surface membrane (sarcolemma) are described using equations for these known currents in mammalian pacemaker cells. The extracellular environment is treated as a diffusion-limited space, and the myoplasm contains Ca(2+)-binding proteins (calmodulin and troponin). Original features of this model include 1) new equations for the hyperpolarization-activated inward current, 2) assessment of the role of the transient-type Ca2+ current during pacemaker depolarization, 3) inclusion of an Na+ current based on recent experimental data, and 4) demonstration of the possible influence of pump and exchanger currents and background currents on the pacemaker rate. This model provides acceptable fits to voltage-clamp and action potential data and can be used to seek biophysically based explanations of the electrophysiological activity in the rabbit sinoatrial node cell.


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