Conditions under which Na+channels can boost conduction of small graded potentials

Taylor, G. C., Coles, J. A. and Eilbeck, J. C. (1995) Conditions under which Na+channels can boost conduction of small graded potentials. Journal of Theoretical Biology, 172(4), pp. 379-386. (doi: 10.1006/jtbi.1995.0035)

Abstract

It has recently become apparent that in the dendrites or short axons of some neurons, voltage-dependent sodium channels are used not to generate action potentials but to modulate graded potentials; graded potentials carry far more information than do action potentials. A model axon (or dendrite) is described in which sodium channels with kinetics described by equations of the Hodgkin-Huxley type boost conduction of small voltage signals. For a sodium channel density beyond a certain minimum there exists an optimal potential, depolarized with respect to the resting potential, at which there is no steady-state decrement along the axon. For an axon not longer than about 0.7 length constants, small, steady-state deviations from this optimal potential imposed at one end of the axon appear amplified in a graded and stable way at the other end. A small pulse of potential is propagated with amplification and more rapidly than in an axon with a passive membrane. Compared to passive propagation, there will be an improvement in signal-to-noise ratio at the synapse; the axon also acts as a selective frequency filter. The same axon is capable of conducting an action potential.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Coles, Dr Jonathan
• Authors: Taylor, G. C., Coles, J. A., and Eilbeck, J. C.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: Journal of Theoretical Biology
• Publisher: Elsevier
• ISSN: 0022-5193
• ISSN (Online): 1095-8541