Voltage Dependence and Time Dependence of Contraction in Sheep Cardiac Purkinje Fibers
- 1 April 1971
- journal article
- research article
- Published by Wolters Kluwer Health in Circulation Research
- Vol. 28 (4), 446-460
- https://doi.org/10.1161/01.res.28.4.446
Abstract
Contractile behavior of the sheep cardiac Purkinje fiber was examined under voltage-clamp conditions in Tyrode's solution. For square depolarizing clamps to a given voltage, peak twitch tension depended on clamp duration if the duration was less than 80 to 90 msec, but measurable contractions could be obtained following 2-msec square clamps. Time to peak tension at 37°C remained constant as clamp duration was shortened. Twitch tension also depended on clamp voltage. The voltage at which tension was first seen, the position of the voltage-tension curve on the voltage axis, and the shape of the curve all were altered by a shift in the steady membrane voltage. After a contraction, recovery of the contractile system was voltage-dependent; recovery was complete in approximately 2 seconds if the muscle was repolarized to potentials more negative than -75 mv, and no recovery was found at potentials more positive than -20 mv. Step changes of voltage to potentials just below tension threshold rapidly inactivated the contractile mechanism without development of tension. These results show a voltage dependence and time dependence of the contractile mechanism which may be of considerable importance to understanding excitation-contraction coupling.Keywords
This publication has 28 references indexed in Scilit:
- The Structural Implications of the Linear Electrical Properties of Cardiac Purkinje StrandsThe Journal of general physiology, 1970
- Differences in contracture development of ventricular and atrial preparations of mammalian cardiac musclePflügers Archiv - European Journal of Physiology, 1969
- Über die Wirkung von Calcium und Natrium auf die Kaliumkontraktur isolierter MeerschweinchenvorhöfePflügers Archiv - European Journal of Physiology, 1969
- Relationship between Membrane Voltage and Tension in Voltage-clamped Cardiac Purkinje FibresNature, 1968
- The Effect of Calcium on the Mechanical Response of Single Twitch Muscle Fibres of Xenopus LaevisActa Physiologica Scandinavica, 1967
- Nachweis einer nat rlichen elektro-mechanischen Koppelungsinsuffizienz bei Purkinje-F den des Rhesus-AffenPflügers Archiv - European Journal of Physiology, 1967
- Excitation and Excitatin-Contraction Coupling in Cardiac MuscleAnnual Review of Physiology, 1964
- Voltage clamp technique in mammalian cardiac fibresPflügers Archiv - European Journal of Physiology, 1964
- THE FORCE OF CONTRACTION OF THE RABBIT PAPILLARY MUSCLE PREPARATION AS A FUNCTION OF THE FREQUENCY AND PATTERN OF STIMULATIONImmunology & Cell Biology, 1962
- Aktionspotential und Mechanogramm von Purkinje-Fäden in tiefer TemperaturPflügers Archiv - European Journal of Physiology, 1961