THE CHANGES OF IMPEDANCE OF THE TURTLE'S VENTRICULAR MUSCLE DURING CONTRACTION

Abstract

The changes of electrical impedance during the activity of the turtle''s ventricle were measured by means of an alternating current bridge and recorded from a cathode-ray oscillograph. The impedance to alternating currents of 30 to 10,000 cycles/sec. and of 0.04 to 0.06 ma. increased during activity. The increase began approx. at the same time as contraction, but it outlasted the mechanical events. There was no parallelism between the impedogram and the electrogram. Brief electrical and mechanical responses involved a brief impedance variation. Upon repetitive stimulation a long enduring impedance change might ensue. The early part of the ventricular electrogram was not attended by any striking change of impedance.