The Sinus Node pp 290-298 | Cite as

General Conclusions

  • W. Trautwein


In this and the previous sections the sinus node was roughly described as a cluster of cells with the special property to depolarize spontaneously in diastole, eventually to the threshold of the next action potential. The cells in the cluster are electrically coupled. Not much has been said about the passive electrical properties of the cells and of the electrical coupling. The length constant seems to be less than 1 mm. The coupling enforces a certain synchrony in the activity of the cells. In microelectrode studies, therefore, one has to keep in mind that an electrode in one cell “sees” events occurring up to one mm away. Yet it is known that the cells in the sinus node do not have all the same ability to “spontaneously” depolarize after an action potential. There is a center normally in the head of the sinus node, the pacemaker, and there are other areas in the sinus node which show diastolic depolarization at a lesser rate and which are excited by propagation. Under certain conditions the pacemaker can shift from one area to another, as shown-in this section-by mapping the spread of excitation.


Sinus Node Pacemaker Cell Sinus Venosus Voltage Clamp Experiment Pacemaker Potential 
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  1. Bozler, E.: The initiation of impulses in cardiac muscle. Amer J Physiol 138: 273, 1943Google Scholar
  2. Dudel, J., Trautwein, W.: Der Mechanismus der automatischen rhythmischen Impulsbildung der Herzmuskelfaser. Pflügers Arch 267: 553, 1958PubMedCrossRefGoogle Scholar
  3. Giles, W., Noble, S.J.: Changes in membrane currents in Bullfrog atrium produced by acetylcholine. J Physiol 261: 103, 1976PubMedGoogle Scholar
  4. Hutter, O.F., Trautwein, W.: Vagal and sympathetic effects on the pacemaker fibres in the sinus venosus of the heart. J gen Physiol 39: 715, 1956PubMedCrossRefGoogle Scholar
  5. Ikemoto, Y., Goto, M.: Nature of the negative inotropic effect of acetylcholine on the myocardium. An elucidation on the bullfrog atrium. Proc Japan Acad 51: 501, 1975Google Scholar
  6. McDonald, T.F., Trautwein, W.: The potassium current underlying delayed rectification in cat ventricular muscle. J. Physiol 274: 217, 1978PubMedGoogle Scholar
  7. Nawrath H.: Does cyclic GMP mediate the negative inotropic effect of acetylcholine in the heart. Nature 267: 72, 1977PubMedCrossRefGoogle Scholar
  8. Noble, D.: The initiation of the heart beat. Oxford University Press, 1975Google Scholar
  9. Ten Eick, R.E., Nawrath, H., McDonald, T.F., Trautwein, W.: On the Mechanism of the Negative Inotropic Effect of Acetylcholine. Pflügers Arch 361: 207, 1976CrossRefGoogle Scholar
  10. Trautwein, W., Dudel, J.: Zum Mechanismus der Membranwirkung des Acetylcholin an der Herzmuskelfaser. Pflügers Arch 266: 324, 1958aPubMedCrossRefGoogle Scholar
  11. Trautwein, W., Dudel, J.: Hemmende und “erregende” Wirkungen des Acethylcholin am Warmbluter-herzen. Zur Frage der spontanen Erregungsbildung. Pflügers Arch 266: 653, 1958bGoogle Scholar
  12. Weidmann S.: Effect of current flow on the membrane potential of cardiac muscle. J Physiol 115: 227, 1951PubMedGoogle Scholar

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© Martinus Nijhoff Medical Division 1978

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  • W. Trautwein

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