A proposed relationship between circumference and conduction velocity of unmyelinated axons from normal and regenerated cat hindlimb cutaneous nerves

Data on the conduction velocities and circumferences of unmyelinated axons in cat hindlimb nerves obtained in two laboratories, each working independently of the other, have been brought together and compared. Results were obtained from normal, regenerated and deafferented nerves. Matching the conduction velocity and circumference distributions against one another suggested that conduction velocity (theta), in m/s, is linearly related to circumference (s), in microns, according to the equation theta = 0.24s. If this relationship is correct, it applies equally well to both sympathetic postganglionic and unmyelinated afferent axons.

[1]  H. S. Gasser,et al.  AXON DIAMETERS IN RELATION TO THE SPIKE DIMENSIONS AND THE CONDUCTION VELOCITY IN MAMMALIAN A FIBERS , 1939 .

[2]  J. Stevens,et al.  Irregular geometries in normal unmyelinated axons: A 3D serial EM analysis , 1990, Journal of neurocytology.

[3]  W. Jänig,et al.  Changes in unmyelinated fibers including sympathetic postganglionic fibers of a skin nerve after peripheral neuroma formation. , 1982, Journal of the autonomic nervous system.

[4]  Alwyn C. Scott,et al.  The electrophysics of a nerve fiber , 1975 .

[5]  W. Jänig,et al.  The cell bodies of origin of sympathetic and sensory axons in some skin and muscle nerves of the cat hindlimb , 1983, The Journal of comparative neurology.

[6]  B. Lynn,et al.  Long‐Term Reduction in the Number of C‐Fibre Nociceptors Following Capsaicin Treatment of a Cutaneous Nerve in Adult Rats , 1990, The European journal of neuroscience.

[7]  A. Paintal.  A comparison of the nerve impulses of mammalian non‐medullated nerve fibres with those of the smallest diameter medullated fibres , 1967, The Journal of physiology.

[8]  W. Jänig,et al.  Organization of the lumbar sympathetic outflow to skeletal muscle and skin of the cat hindlimb and tail. , 1985, Reviews of physiology, biochemistry and pharmacology.

[9]  H. S. Gasser.  UNMEDULLATED FIBERS ORIGINATING IN DORSAL ROOT GANGLIA , 1950, The Journal of general physiology.

[10]  I. A. Boyd,et al.  Ultrastructural dimensions of myelinated peripheral nerve fibres in the cat and their relation to conduction velocity , 1980, The Journal of physiology.

[11]  K G Pearson,et al.  Predicted amplitude and form of action potentials recorded from unmyelinated nerve fibres. , 1971, Journal of theoretical biology.

[12]  A. Hodgkin.  The optimum density of sodium channels in an unmyelinated nerve. , 1975, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[13]  D. J. Aidley.  The physiology of excitable cells , 1971 .

[14]  The proportions of sympathetic postganglionic and unmyelinated afferent axons in normal and regenerated cat sural nerves. , 1988, Journal of the autonomic nervous system.

[15]  J. M. Ritchie,et al.  The binding of saxitoxin and tetrodotoxin to excitable tissue. , 1977, Reviews of physiology, biochemistry and pharmacology.

[16]  A. Hodgkin,et al.  A note on conduction velocity , 1954, The Journal of physiology.

[17]  K G Pearson,et al.  Properties of action potentials from insect motor nerve fibres. , 1970, The Journal of experimental biology.

[18]  J. Jack,et al.  Electric current flow in excitable cells , 1975 .

[19]  J. Hursh.  CONDUCTION VELOCITY AND DIAMETER OF NERVE FIBERS , 1939 .

[20]  I. A. Boyd,et al.  Scaling factor relating conduction velocity and diameter for myelinated afferent nerve fibres in the cat hind limb. , 1979, The Journal of physiology.

[21]  R. Hodes.  Linear relationship between fiber diameter and velocity of conduction in giant axon of squid. , 1953, Journal of neurophysiology.

[22]  Jack Jj.  Physiology of peripheral nerve fibres in relation to their size. , 1975 .

[23]  J. Young,et al.  The Rates Of Conduction Of Nerve Fibres Of Various Diameters In Cephalopods , 1938 .

[24]  B. Lynn.  Effect of neonatal treatment with capsaicin on the numbers and properties of cutaneous afferent units from the hairy skin of the rat , 1984, Brain Research.