The electrogram from sinus venosus of toad recorded in vitro and the effect of high concentration of potassium and calcium on it

Abstract

Using direct extracellular lead the electrical activity of toad’s sinus venosus may he recorded by electrocardiograph. Ordinarily two waves could be recorded in each cycle and were named wave N and wave P respectively. Intracellular recording indicates that wave N reflects the electrical activity of the pacemaker cells while wave P reflects that of the working cells situated in sinus venosus or atrial cells.

We have observed the effect of high potassium, high potassium plus calcium on the activity of sinus venosus. The results indicate that high potassium evokes intrasinal or sinoatrial block and thus slows the cardiac rhythm which can be antagonized by high calcium

Keywords

electrosinovenosogram / sinus venosus / pacemaker cell / working cell

References

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