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. 1981 Sep;318:25–39. doi: 10.1113/jphysiol.1981.sp013848

Effects of cutaneous nerve and intraspinal conditioning of C-fibre afferent terminal excitability in decerebrate spinal rats.

M Fitzgerald, C J Woolf
PMCID: PMC1245475  PMID: 7320890

Abstract

1. Changes in the threshold for antidromic activation of C-fibre afferent terminals in the lumbar spinal cord of the decerebrate-spinalized rat have been examined. 2. The antidromic compound action potential elicited by stimulation in the dorsal horn was recorded in a sectioned dorsal root. 3. The antidromic C wave had conduction velocities and strength-duration properties similar to that described for other unmyelinated fibres. 4. The optimal position of the stimulating electrode within the spinal cord for eliciting the antidromic C wave was found to correlate with the site of entry and termination of C-afferent fibres. 5. Local stimulation within the dorsal grey of the spinal cord was shown to produce prolonged increased excitability of the C-afferent terminals in that segment. This effect was restricted to the terminals and could not be demonstrated in the stem axons of the C fibres. 6. Cutaneous afferent conditioning volleys from the sural nerve produced marked increases in the excitability of the C-afferent terminals. This effect was present at A-fibre strength sural stimulation, with no significant alteration when C-fibre strength stimulation was used. The alteration in the threshold for antidromic stimulation produced by the sural conditioning stimuli only occurred at the C-afferent terminals and not at their axons. 7. The results are discussed in terms of presynaptic inhibition of C-fibre input at a segmental level.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Brown A. G., Kirk E. J., Martin H. F., 3rd Descending and segmental inhibition of transmission through the spinocervical tract. J Physiol. 1973 May;230(3):689–705. doi: 10.1113/jphysiol.1973.sp010212. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Cervero F., Iggo A., Ogawa H. Nociceptor-driven dorsal horn neurones in the lumbar spinal cord of the cat. Pain. 1976 Mar;2(1):5–24. doi: 10.1016/0304-3959(76)90042-7. [DOI] [PubMed] [Google Scholar]
  3. DOUGLAS W. W., RITCHIE J. M. Mammalian nonmyelinated nerve fibers. Physiol Rev. 1962 Apr;42:297–334. doi: 10.1152/physrev.1962.42.2.297. [DOI] [PubMed] [Google Scholar]
  4. ECCLES J. C., ECCLES R. M., MAGNI F. Central inhibitory action attributable to presynaptic depolarization produced by muscle afferent volleys. J Physiol. 1961 Nov;159:147–166. doi: 10.1113/jphysiol.1961.sp006798. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Fields H. L., Basbaum A. I. Brainstem control of spinal pain-transmission neurons. Annu Rev Physiol. 1978;40:217–248. doi: 10.1146/annurev.ph.40.030178.001245. [DOI] [PubMed] [Google Scholar]
  6. GASSER H. S. Properties of dorsal root unmedullated fibers on the two sides of the ganglion. J Gen Physiol. 1955 May 20;38(5):709–728. doi: 10.1085/jgp.38.5.709. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. GASSER H. S. The postspike positivity of unmedullated fibers of dorsal root origin. J Gen Physiol. 1958 Mar 20;41(4):613–632. doi: 10.1085/jgp.41.4.613. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. HOWLAND B., LETTVIN J. Y., McCULLOCH W. S., PITTS W., WALL P. D. Reflex inhibition by dorsal root interaction. J Neurophysiol. 1955 Jan;18(1):1–17. doi: 10.1152/jn.1955.18.1.1. [DOI] [PubMed] [Google Scholar]
  9. Handwerker H. O., Iggo A., Zimmermann M. Segmental and supraspinal actions on dorsal horn neurons responding to noxious and non-noxious skin stimuli. Pain. 1975 Jun;1(2):147–165. doi: 10.1016/0304-3959(75)90099-8. [DOI] [PubMed] [Google Scholar]
  10. Hentall I. D., Fields H. L. Segmental and descending influences on intraspinal thresholds of single C-fibers. J Neurophysiol. 1979 Nov;42(6):1527–1537. doi: 10.1152/jn.1979.42.6.1527. [DOI] [PubMed] [Google Scholar]
  11. Hodge C. J., Jr Potential changes inside central afferent terminals secondary to stimulation of large- and small-diameter peripheral nerve fibers. J Neurophysiol. 1972 Jan;35(1):30–43. doi: 10.1152/jn.1972.35.1.30. [DOI] [PubMed] [Google Scholar]
  12. Kennedy D., McVittie J., Calabrese R., Fricke R. A., Craelius W., Chiapella P. Inhibition of mechanosensory interneurons in the crayfish. I. Presynaptic inhibition from giant fibers. J Neurophysiol. 1980 Jun;43(6):1495–1509. doi: 10.1152/jn.1980.43.6.1495. [DOI] [PubMed] [Google Scholar]
  13. Krnjević K., Morris M. E. Input-output relation of transmission through cuneate nucleus. J Physiol. 1976 Jun;257(3):791–815. doi: 10.1113/jphysiol.1976.sp011398. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Lisney S. J. Evidence for primary afferent depolarization of single tooth-pulp afferents in the cat. J Physiol. 1979 Mar;288:437–447. [PMC free article] [PubMed] [Google Scholar]
  15. Mendell L. M. Physiological properties of unmyelinated fiber projection to the spinal cord. Exp Neurol. 1966 Nov;16(3):316–332. doi: 10.1016/0014-4886(66)90068-9. [DOI] [PubMed] [Google Scholar]
  16. Merrill E. G., Wall P. D., Yaksh T. L. Properties of two unmyelinated fibre tracts of the central nervous system: lateral Lissauer tract, and parallel fibres of the cerebellum. J Physiol. 1978 Nov;284:127–145. doi: 10.1113/jphysiol.1978.sp012531. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Ranck J. B., Jr Which elements are excited in electrical stimulation of mammalian central nervous system: a review. Brain Res. 1975 Nov 21;98(3):417–440. doi: 10.1016/0006-8993(75)90364-9. [DOI] [PubMed] [Google Scholar]
  18. Réthelyi M. Preterminal and terminal axon arborizations in the substantia gelatinosa of cat's spinal cord. J Comp Neurol. 1977 Apr 1;172(3):511–521. doi: 10.1002/cne.901720307. [DOI] [PubMed] [Google Scholar]
  19. Shapiro E., Castellucci V. F., Kandel E. R. Presynaptic inhibition in Aplysia involves a decrease in the Ca2+ current of the presynaptic neuron. Proc Natl Acad Sci U S A. 1980 Feb;77(2):1185–1189. doi: 10.1073/pnas.77.2.1185. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. WALL P. D. Excitability changes in afferent fibre terminations and their relation to slow potentials. J Physiol. 1958 Jun 18;142(1):1–21. doi: 10.1113/jphysiol.1958.sp005997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Wall P. D., Sweet W. H. Temporary abolition of pain in man. Science. 1967 Jan 6;155(3758):108–109. doi: 10.1126/science.155.3758.108. [DOI] [PubMed] [Google Scholar]
  22. Wall P. D. The role of substantia gelatinosa as a gate control. Res Publ Assoc Res Nerv Ment Dis. 1980;58:205–231. [PubMed] [Google Scholar]
  23. Woolf C. J., Mitchell D., Barrett G. D. Antinociceptive effect of peripheral segmental electrical stimulation in the rat. Pain. 1980 Apr;8(2):237–252. doi: 10.1016/0304-3959(88)90011-5. [DOI] [PubMed] [Google Scholar]

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