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Bistable nerve conduction

delete2022-09-01
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Zhaoyang Zhang
Z
Zhilin Qu *
DOI:10.1016/j.bpj.2022.08.006delete
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Abstract

Abstract

En 中文
It has been demonstrated experimentally that slow and fast conduction waves with distinct conduction velocities can occur in the same nerve system depending on the strength or the form of the stimulus, which give rise to two modes of nerve functions. However, the mechanisms remain to be elucidated. In this study, we use computer simulations of the cable equation with modified Hodgkin-Huxley kinetics and analytical solutions of a simplified model to show that stimulus-dependent slow and fast waves recapitulating the experimental observations can occur in the cable, which are the two stable conduction states of a bistable conduction behavior. The bistable conduction is caused by a positive feedback loop of the wavefront upstroke speed, mediated by the sodium channel inactivation properties. Although the occurrence of bistable conduction only requires the pres-ence of the sodium current, adding a calcium current to the model further promotes bistable conduction by potentiating the slow wave. We also show that the bistable conduction is robust, occurring for sodium and calcium activation thresholds well within the experimentally determined ones of the known sodium and calcium channel families. Since bistable conduction can occur in the cable equation of Hodgkin-Huxley kinetics with a single inward current, i.e., the sodium current, it can be a generic mechanism applicable to stimulus-dependent fast and slow conduction not only in the nerve systems but also in other electrically excitable systems, such as cardiac muscles.
Keywords:
UNION-OF-PHARMACOLOGY
GIANT MOTOR AXONS
VELOCITY DISTRIBUTIONS
ACTION-POTENTIALS
PROPAGATION
NOMENCLATURE
DIAMETER
CURRENTS
SODIUM
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Journal

Biophysical Journal cover
Biophysical Journal
IF:
3.1
Papers:
5.0W
Citations:
4.4W

Organization

University of California System cover
University of California System
Scholars:
37.5W
Papers: 33.7W
Citations: 6.6K