Journal article
Simulation of propagation in a bundle of skeletal muscle fibers: Modulation effects of passive fibers
Computer simulations are used to study passive fiber modulation of propagation in a tightly packed bundle of frog skeletal muscle fibers (uniform fiber radius of 50 mu m). With T = 20 degrees C and a uniform nominal interstitial cleft width (d) over bar = 0.35 mu m, about 92% of the active fiber source current (I-ma) enters the passive tissue as a radial load current (I-ep) while the rest flows longitudinally in the cleft between the active and adjacent passive fibers.
The conduction velocity of 1.32 m/s was about 30% lower than on an isolated fiber in a Ringer bath, in close agreement with experimental results. The peak-to-peak interstitial potential (phi(epp)) at the active fiber surface was 38 mV, compared to 1.3 mV for the isolated fiber. A uniform increase of d from 0.35 to 1.2 mu m decreased phi(epp) from 38 to 25 mV, increased the velocity from 1.32 to 1.54 m/s, and decreased the maximum rate of rise of the action potential upstroke (V-max) from 512 to 503 V/s.
Increasing the phase angle of the passive fiber membrane impedence (Z(m)) increases the phase delay between I-ma and I-ep, thereby increasing phi(epp) which in turn slows down propagation and increases V-max.
Language: | English |
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Publisher: | Springer US |
Year: | 1997 |
Pages: | 29-45 |
ISSN: | 15739686 , 00906964 and 15216047 |
Types: | Journal article |
DOI: | 10.1007/BF02738536 |
ORCIDs: | Henneberg, Kaj-åge |
Action Potentials Action potential propagation Animals Anura Bidomain Computer Simulation Conduction velocity Electric Impedance Electrophysiology Fiber packing density Interstitial space Maximum rate of rise Membrane impedance Modeling Models, Biological Muscle Fibers, Skeletal Muscle, Skeletal Transverse tubular system