title: Ventral root afferent and dorsal root efferent fibres in dog and human lower sacral nerve roots.
abstract: Two pairs of wire electrodes were used to record single afferent action potentials from ventral roots and single efferent action potentials from dorsal roots of dogs and humans. A human lower sacral ventral root contained about 20 to 30% afferents among fibres with a diameter larger than 5 microns; a comparable ventral root of a dog contained about 1% afferents. Human S3, S4 and S5 dorsal roots contained 3, 18, and 20 to 30% efferent fibres respectively; a comparable dorsal root of the dog contained less than 1% efferent fibres. Primary and secondary muscle spindle afferents, Golgi tendon organ afferents, and afferents from the mechanoreceptors of the urinary bladder and anal canal mucosa were activated in a dog ventral root by pulling bladder and anal catheters. Their peak group conduction velocities were 82, 57, 71 and 18 m/s at 34 degrees C respectively. The dog afferents conducted more than 30% faster than did comparable human nerve fibres. By strongly pulling the bladder catheter, the static human dorsal root gamma 21-motoneurons increased their activity for about 7 s which in turn strongly increased the dorsal root spindle afferent activity for more than 10 min; the human static intrafusal gamma-motoneurons seemed to show cumulative properties.
authors.affiliation: Department of Neuropathology, Freie Universität Berlin, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Schalow
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D001003:Anal Canal / Q000294:innervation; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D004285:Dogs; D004525:Efferent Pathways / Q000502:physiology; D004594:Electrophysiology; D006801:Humans; D009412:Nerve Fibers / Q000502:physiology* / Q000648:ultrastructure; D009431:Neural Conduction / Q000502:physiology; D012445:Sacrococcygeal Region; D013045:Species Specificity; D013126:Spinal Nerve Roots / Q000502:physiology*; D001743:Urinary Bladder / Q000294:innervation