Effects of extracellular potassium on ventricular automaticity and evidence for a pacemaker current in mammalian ventricular myocardium

Circulation Research
B Katzung, J A Morgenstern


Automaticity was induced in isolated guinea pig and cat papillary muscles by application of depolarizing constant current pulses. Increasing extracellular potassium from 1 to 15 mM caused a shift of pacemaker-like activity to less negative diastolic potentials and a decrease in maximum phase 4 slope. Membrane resistance, estimated from the relation of applied current to maximum diastolic potential, decreased when extracellular potassium was increased. Voltage clamps of cat papillary muscle demonstrated that action potentials activate a time-dependent outward current which has a reversal potential of -79.1 mV (+/- 0.99 SE, n = 20) at an extracellular potassium concentration of 5 mM. The reversal potential of this current varies with extracellular K+ with a slope of 50-60 mV per 10-fold concentration change. The current is activated by voltage clamps or action potential plateaus in the range of -30 to +30 mV. It has a time constant of deactivation which increases from approximately 100 to over 400 msec as clamp potential is increased from -90 to -60 mV. It is proposed that this current is equivalent to Ix1 demonstrated in other cardiac tissues and is responsible, in combination with inward currents, for automaticity in ventricula...Continue Reading


Jun 1, 1975·The Journal of General Physiology·C O Lee, H A Fozzard
Oct 28, 1975·Pflügers Archiv : European journal of physiology·B KatzungA O Grant
Jan 1, 1976·The Journal of Physiology·E E CarmelietJ S Vereecke
Jan 1, 1971·Naunyn-Schmiedebergs Archiv Für Pharmakologie·H Antoni
Sep 1, 1974·The Journal of General Physiology·R W Tsien
Jun 1, 1973·The Journal of General Physiology·R S Aronson, P F Cranefield
Jan 11, 1974·Pflügers Archiv : European journal of physiology·R S Aronson, P F Cranefield
Jan 1, 1971·Annual Review of Physiology·E A Johnson, M Lieberman
Feb 1, 1972·The Journal of General Physiology·P F CranefieldB F Hoffman
Jan 1, 1972·Pflügers Archiv : European journal of physiology·W New, W Trautwein
Oct 1, 1970·The American Journal of Physiology·K Hermsmeyer, N SPERELAKIS
Mar 1, 1970·The Journal of Physiology·G W Beeler, H Reuter
Nov 1, 1960·The Journal of General Physiology·E PAGE, A K SOLOMON
May 1, 1964·The Journal of General Physiology·N SPERELAKIS, D LEHMKUHL


Dec 1, 1987·Pflügers Archiv : European journal of physiology·H MatsuuraY Imoto
Oct 1, 1979·Pflügers Archiv : European journal of physiology·A J Pappano, E E Carmeliet
Jan 1, 1991·International Journal of Cardiac Imaging·N el-Sherif
Oct 15, 1987·Experientia·B F Hoffman, K H Dangman
Apr 23, 1982·European Journal of Pharmacology·H S Karagueuzian, B Katzung
Jan 1, 1980·Progress in Biophysics and Molecular Biology·M R Boyett, B R Jewell
Aug 29, 1996·The American Journal of Cardiology·P A Boyden
Jun 1, 1985·Journal of the American College of Cardiology·B Surawicz
Jun 29, 1999·British Journal of Pharmacology·T NakajimaH Hazama
Jun 1, 1986·British Heart Journal·S C Webb, P A Poole-Wilson
Mar 3, 1980·Klinische Wochenschrift·C Naumann d'AlnoncourtD Durrer
Jan 1, 1984·Annals of the New York Academy of Sciences·A L Wit
Dec 24, 1997·Cardiology Clinics·C Cabo, A L Wit
Jun 30, 2010·Fundamental & Clinical Pharmacology·O E Osadchii
Aug 6, 2014·Journal of Cellular and Molecular Medicine·Dan ShiYi-Han Chen
Jul 1, 1982·IEEE Transactions on Bio-medical Engineering·J P Drouhard, F A Roberge
Oct 1, 1988·Journal of Cardiothoracic Anesthesia·S E McNultyJ L Seltzer
Oct 1, 1983·American Heart Journal·A L Wit, M R Rosen
Jan 1, 1988·Annals of the New York Academy of Sciences·L H OpieF T Thandroyen
Oct 1, 1982·British Journal of Pharmacology·F Riccioppo Neto
Dec 7, 1990·Journal of Theoretical Biology·A Vinet, F A Roberge
Jul 5, 2005·Heart Rhythm : the Official Journal of the Heart Rhythm Society·Rashmi R Shah, L M Hondeghem
Apr 9, 2009·Progress in Biophysics and Molecular Biology·Morten GrunnetSøren-Peter Olesen
Jul 1, 1981·Circulation Research·B F Hoffman, M R Rosen
Jan 1, 1986·Journal of Perinatal Medicine·M R Boyett
Jul 3, 1999·Physiological Reviews·E E Carmeliet
Jul 25, 2020·Journal of Intensive Care Medicine·Janek M SenaratneSean van Diepen

Related Concepts

Related Feeds

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.