Skip to main content
PMC home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1993 Jul;466:191–211.

Convergence in segmental reflex pathways from nociceptive and non-nociceptive afferents to alpha-motoneurones in the cat.

H Steffens 1, E D Schomburg 1
PMCID: PMC1175474  PMID: 8410691

Abstract

1. Reflex interaction between nociceptive and non-nociceptive segmental afferents was investigated by testing for spatial facilitation of postsynaptic potentials (PSPs) in alpha-motoneurones recorded in anaemically decapitated, high spinal cats. Nociceptive segmental afferents were activated by applying noxious radiant heat to the skin. Non-nociceptive skin mechanoreceptors were activated by puffs of air. Non-nociceptive skin, joint and group I-III muscle afferents were stimulated by electrical pulses delivered to various nerves. 2. Conditioning by stimulation of nociceptive afferents facilitated transmission in various ipsilateral segmental pathways. Such spatial facilitation occurred in both excitatory and inhibitory pathways. Pathways that were facilitated included those activated by low to medium threshold cutaneous afferents, joint afferents, and group Ib and II muscle afferents. 3. In contrast, monosynaptic EPSPs evoked by stimulating ipsilateral group Ia muscle afferents did not show spatial facilitation but rather inhibition during conditioning stimulation of nociceptive afferents. Spatial facilitation of reciprocal group Ia IPSPs was rare and small if it occurred. 4. Pathways activated by cutaneous and group II muscle afferents were depressed by contralateral stimulation of nociceptive afferents. 5. We conclude that spatial facilitation observed between nociceptive and non-nociceptive afferents results from a convergence of inputs on common interneurones in the reflex pathways to alpha-motoneurones. Therefore nociceptive afferents have to be regarded as constituents of flexor reflex afferents (FRAs) and may add a specific nocifensive function to the FRA system.

Full text

PDF
211

Selected References

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

  1. Beck P. W., Handwerker H. O., Zimmermann M. Nervous outflow from the cat's foot during noxious radiant heat stimulation. Brain Res. 1974 Mar 8;67(3):373–386. doi: 10.1016/0006-8993(74)90488-0. [DOI] [PubMed] [Google Scholar]
  2. Behrends T., Schomburg E. D., Steffens H. Facilitatory interaction between cutaneous afferents from low threshold mechanoreceptors and nociceptors in segmental reflex pathways to alpha-motoneurons. Brain Res. 1983 Jan 31;260(1):131–134. doi: 10.1016/0006-8993(83)90773-4. [DOI] [PubMed] [Google Scholar]
  3. Besson J. M., Chaouch A. Peripheral and spinal mechanisms of nociception. Physiol Rev. 1987 Jan;67(1):67–186. doi: 10.1152/physrev.1987.67.1.67. [DOI] [PubMed] [Google Scholar]
  4. Burke R. E., Rudomin P., Vyklický L., Zajac F. E., 3rd Primary afferent depolarization and flexion reflexes produced by radiant heat stimulation of the skin. J Physiol. 1971 Feb;213(1):185–214. doi: 10.1113/jphysiol.1971.sp009376. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. ECCLES J. C., ECCLES R. M., LUNDBERG A. Synaptic actions on motoneurones caused by impulses in Golgi tendon organ afferents. J Physiol. 1957 Sep 30;138(2):227–252. doi: 10.1113/jphysiol.1957.sp005849. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Eccles J. C., Magni F., Willis W. D. Depolarization of central terminals of Group I afferent fibres from muscle. J Physiol. 1962 Jan;160(1):62–93. doi: 10.1113/jphysiol.1962.sp006835. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Fedina L., Hultborn H. Facilitation from ipsilateral primary afferents of interneuronal transmission in the Ia inhibitory pathway to motoneurones. Acta Physiol Scand. 1972 Sep;86(1):59–81. doi: 10.1111/j.1748-1716.1972.tb00225.x. [DOI] [PubMed] [Google Scholar]
  8. Fitzgerald M., Lynn B. The sensitization of high threshold mechanoreceptors with myelinated axons by repeated heating. J Physiol. 1977 Feb;265(2):549–563. doi: 10.1113/jphysiol.1977.sp011730. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Grillner S., Hongo T. Vestibulospinal effects on motoneurones and interneurones in the lumbosacral cord. Prog Brain Res. 1972;37:243–262. doi: 10.1016/S0079-6123(08)63906-0. [DOI] [PubMed] [Google Scholar]
  10. Harrison P. J., Jankowska E. Sources of input to interneurones mediating group I non-reciprocal inhibition of motoneurones in the cat. J Physiol. 1985 Apr;361:379–401. doi: 10.1113/jphysiol.1985.sp015651. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Harrison P. J., Jankowska E., Zytnicki D. Lamina VIII interneurones interposed in crossed reflex pathways in the cat. J Physiol. 1986 Feb;371:147–166. doi: 10.1113/jphysiol.1986.sp015965. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hultborn H. Convergence on interneurones in the reciprocal Ia inhibitory pathway to motoneurones. Acta Physiol Scand Suppl. 1972;375:1–42. doi: 10.1111/j.1748-1716.1972.tb05298.x. [DOI] [PubMed] [Google Scholar]
  13. Hultborn H., Illert M., Santini M. Convergence on interneurones mediating the reciprocal Ia inhibition of motoneurones. I. Disynaptic Ia inhibition of Ia inhibitory interneurones. Acta Physiol Scand. 1976 Feb;96(2):193–201. doi: 10.1111/j.1748-1716.1976.tb10188.x. [DOI] [PubMed] [Google Scholar]
  14. Hultborn H. Transmission in the pathway of reciprocal Ia inhibition to motoneurones and its control during the tonic stretch reflex. Prog Brain Res. 1976;44:235–255. doi: 10.1016/S0079-6123(08)60736-0. [DOI] [PubMed] [Google Scholar]
  15. Jankowska E. Interneuronal relay in spinal pathways from proprioceptors. Prog Neurobiol. 1992;38(4):335–378. doi: 10.1016/0301-0082(92)90024-9. [DOI] [PubMed] [Google Scholar]
  16. Jankowska E., McCrea D. A. Shared reflex pathways from Ib tendon organ afferents and Ia muscle spindle afferents in the cat. J Physiol. 1983 May;338:99–111. doi: 10.1113/jphysiol.1983.sp014663. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Jänig W., Zimmermann M. Presynaptic depolarization of myelinated afferent fibres evoked by stimulation of cutaneous C fibres. J Physiol. 1971 Apr;214(1):29–50. doi: 10.1113/jphysiol.1971.sp009417. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Kirkwood P. A., Schomburg E. D., Steffens H. Facilitatory interaction in spinal reflex pathways from nociceptive cutaneous afferents and identified secondary spindle afferents in the cat. Exp Brain Res. 1987;68(3):657–660. doi: 10.1007/BF00249808. [DOI] [PubMed] [Google Scholar]
  19. Kniffki K. D., Schomburg E. D., Steffens H. Effects from fine muscle and cutaneous afferents on spinal locomotion in cats. J Physiol. 1981;319:543–554. doi: 10.1113/jphysiol.1981.sp013925. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Lundberg A. Convergence of excitatory and inhibitory action on interneurones in the spinal cord. UCLA Forum Med Sci. 1969;11:231–265. [PubMed] [Google Scholar]
  21. Lundberg A., Malmgren K., Schomburg E. D. Cutaneous facilitation of transmission in reflex pathways from Ib afferents to motoneurones. J Physiol. 1977 Mar;265(3):763–780. doi: 10.1113/jphysiol.1977.sp011742. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Lundberg A., Malmgren K., Schomburg E. D. Reflex pathways from group II muscle afferents. 1. Distribution and linkage of reflex actions to alpha-motoneurones. Exp Brain Res. 1987;65(2):271–281. doi: 10.1007/BF00236299. [DOI] [PubMed] [Google Scholar]
  23. Lundberg A., Malmgren K., Schomburg E. D. Reflex pathways from group II muscle afferents. 2. Functional characteristics of reflex pathways to alpha-motoneurones. Exp Brain Res. 1987;65(2):282–293. doi: 10.1007/BF00236300. [DOI] [PubMed] [Google Scholar]
  24. Lundberg A., Malmgren K., Schomburg E. D. Reflex pathways from group II muscle afferents. 3. Secondary spindle afferents and the FRA: a new hypothesis. Exp Brain Res. 1987;65(2):294–306. doi: 10.1007/BF00236301. [DOI] [PubMed] [Google Scholar]
  25. Lundberg A., Malmgren K., Schomburg E. D. Role of joint afferents in motor control exemplified by effects on reflex pathways from Ib afferents. J Physiol. 1978 Nov;284:327–343. doi: 10.1113/jphysiol.1978.sp012543. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Lundberg A. Multisensory control of spinal reflex pathways. Prog Brain Res. 1979;50:11–28. doi: 10.1016/S0079-6123(08)60803-1. [DOI] [PubMed] [Google Scholar]
  27. Schomburg E. D. Spinal sensorimotor systems and their supraspinal control. Neurosci Res. 1990 Feb;7(4):265–340. doi: 10.1016/0168-0102(90)90008-3. [DOI] [PubMed] [Google Scholar]
  28. Schomburg E. D., Steffens H. Synaptic responses of lumbar alpha-motoneurones to selective stimulation of cutaneous nociceptors and low threshold mechanoreceptors in the spinal cat. Exp Brain Res. 1986;62(2):335–342. doi: 10.1007/BF00238853. [DOI] [PubMed] [Google Scholar]
  29. Schomburg E. D., Steffens H., Warneke G. Functional organization of the spinal reflex pathways from forelimb afferents to hindlimb motoneurones in the cat. II. Conditions of the interneuronal connections. Brain Res. 1986 Jun 11;375(2):280–290. doi: 10.1016/0006-8993(86)90748-1. [DOI] [PubMed] [Google Scholar]
  30. Sherrington C. S. Qualitative difference of spinal reflex corresponding with qualitative difference of cutaneous stimulus. J Physiol. 1903 Aug 24;30(1):39–46. doi: 10.1113/jphysiol.1903.sp000980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Whitehorn D., Burgess P. R. Changes in polarization of central branches of myelinated mechanoreceptor and nociceptor fibers during noxious and innocuous stimulation of the skin. J Neurophysiol. 1973 Mar;36(2):226–237. doi: 10.1152/jn.1973.36.2.226. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES