scholarly journals EFFECTS OF Na+ AND K+ ON THE RESTING MEMBRANE POTENTIAL OF THE RABBIT SINOATRIAL NODE CELL

1975 ◽  
Vol 25 (3) ◽  
pp. 287-302 ◽  
Author(s):  
Akinori NOMA ◽  
Hiroshi IRISAWA
Keyword(s):  
Membrane Potential ◽  
Sinoatrial Node ◽  
Resting Membrane Potential ◽  
Sinoatrial Node Cell ◽  
Rabbit Sinoatrial Node

A mathematical model of a rabbit sinoatrial node cell

1994 ◽  
Vol 266 (3) ◽  
pp. C832-C852 ◽  
Author(s):  
S. S. Demir ◽  
J. W. Clark ◽  
C. R. Murphey ◽  
W. R. Giles
Keyword(s):  
Mathematical Model ◽  
Sinoatrial Node ◽  
Surface Membrane ◽  
Recent Experimental Data ◽  
Pacemaker Cells ◽  
Diffusion Limited ◽  
Electrophysiological Responses ◽  
Sinoatrial Node Cell ◽  
Rabbit Sinoatrial Node

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.

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
Keyword(s):  
Sinoatrial Node ◽  
Slow Inward Current ◽  
Inward Current ◽  
Sinoatrial Node Cell ◽  
Rabbit Sinoatrial Node

Heterogeneity of 4-aminopyridine-sensitive current in rabbit sinoatrial node cells

1999 ◽  
Vol 276 (4) ◽  
pp. H1295-H1304 ◽  
Author(s):  
Haruo Honjo ◽  
Ming Lei ◽  
Mark R. Boyett ◽  
Itsuo Kodama
Keyword(s):  
Membrane Potential ◽  
Regional Differences ◽  
Sinoatrial Node ◽  
Pacemaker Cells ◽  
Electrophysiological Properties ◽  
Sa Node ◽  
Slope Factor ◽  
Ionic Mechanisms ◽  
Rabbit Sinoatrial Node ◽  
Cell Capacitance

The electrophysiological properties of sinoatrial (SA) node pacemaker cells vary in different regions of the node. In this study, we have investigated variation of the 4-aminopyridine (4-AP)-sensitive current as a function of the size (as measured by the cell capacitance) of SA node cells to elucidate the ionic mechanisms. The 10 mM 4-AP-sensitive current recorded from rabbit SA node cells was composed of transient and sustained components ( I trans and I sus, respectively). The activation and inactivation properties [activation: membrane potential at which conductance is half-maximally activated ( V h) = 19.3 mV, slope factor ( k) = 15.0 mV; inactivation: V h= −31.5 mV, k = 7.2 mV] as well as the density of I trans (9.0 pA/pF on average at +50 mV) were independent of cell capacitance. In contrast, the density of I sus (0.97 pA/pF on average at +50 mV) was greater in larger cells, giving rise to a significant correlation with cell capacitance. The greater density of I sus in larger cells (presumably from the periphery) can explain the shorter action potential in the periphery of the SA node compared with that in the center. Thus variation of the 4-AP-sensitive current may be involved in regional differences in repolarization within the SA node.

Inward current of the rabbit sinoatrial node cell

1977 ◽  
Vol 372 (1) ◽  
pp. 43-51 ◽  
Author(s):  
A. Noma ◽  
K. Yanagihara ◽  
H. Irisawa
Keyword(s):  
Sinoatrial Node ◽  
Inward Current ◽  
Sinoatrial Node Cell ◽  
Rabbit Sinoatrial Node
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