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Viscerosomatic somatic convergence at lumbar interneurons in the dorsal horn of the cat and rat spinal cord

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Abstract

In experiments on spinal cats, when branches of the pelvic nerve innervating the rectum were electrically stimulated at the same time as the peroneal nerve it was found that 12 out of 20 neurons, to which the effects of both these supplies converged, were activated by both A- and C-fibers. Responses to stimulation of the pelvic nerve were apparently mediated via fibers with a conduction velocity not less than 2.2 m·s−1. In studies in spinal rats it was shown that distension of the more distal regions of the large intestine could excite neurons in laminae IV–V, and inhibit neurons in deeper laminae. In seven out of 18 cases the inhibition evoked by visceral stimulation was due to a direct effect on the postsynaptic membrane of these cells, and in 11 cases it was localized to presynaptic structures. Naloxone, strychnine, and atropine did not block this inhibition, thus providing evidence against the possible participation of opioids, glycine, and acetylcholine in its generation. Phaclofen, a GABAB-receptor antagonist, was also without effect, but bicuculline suppressed this inhibition in three out of 12 cases, indicating that GABAA-receptors are involved.

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Literature cited

  1. 1.

    A. V. Val'dman, Neuropharmacology of Narcotic Analgesics, Meditsinam, Moscow (1972).

  2. 2.

    A. P. Gokin, "Characteristics of synaptic activation of intermediate neurons in thoracic segments of the spinal cord by cutaneous, muscular and visceral afferents," Neirofiziologiya,2, No. 6, 563–572 (1970).

  3. 3.

    S. W. Ammonds, R. W. Blair, and R. D. Foreman, "Vagal afferent inhibition of primate thoracic spinothalamic neurons," J. Neurophysiol.,50, No. 4, 926–940 (1983).

  4. 4.

    S. W. Ammonds, R. W. Blair, and R. D. Foreman, "Raphe magnus inhibition of primate T1-T4 spinothalamic cells with cardiopulmonary visceral input," Pain,20, No. 3, 247–260 (1984).

  5. 5.

    F. Cervero, "Supraspinal connections of neurones in the thoracic spinal cord of the cat: ascending projections and effects of descending impulses," Brain Res.,275, No. 2, 251–261 (1983).

  6. 6.

    K. Fukai and A. Fukuda, "The intramural pelvic nerves in the colon of dogs," J. Physiol.,354, 89–98 (1984).

  7. 7.

    G. Janiso and C. A. Maggi, "Distribution of capsaicin-sensitive urinary bladder afferents in the rat spinal cord," Brain Res.,418, No. 2, 371–376 (1987).

  8. 8.

    F. M. Jensen, J. B. Madsen, C. V. Ringsted, and A. Christensen, "Intestinal distension test, a method for evaluating intermittent visceral pain in the rabbit," Life Sci.,43, No. 9, 747–754 (1988).

  9. 9.

    D. I. B. Kerr, J. Ong, R. H. Prager, B. D. Gynther. and D. R. Curtis, "Phaclofen: a peripheral and central baclofen antagonist," Brain Res.,405, No. 1–2, 150–154 (1987).

  10. 10.

    I. Nagelhaft and A. M. Booth, "The location and morphology of preganglionic neurons and the distribution of visceral afferents from the rat pelvic nerve: a horseradish peroxidase study," J. Comp. Neurol.,226, No. 2, 238–245 (1984).

  11. 11.

    T. J. Ness and G. F. Gebhart, "Colorectal distension as a noxious visceral stimulus: physiologic and pharmacologic characterization of pseudoactive reflexes in the rat," Brain Res.,450, No. 1–2, 153–169 (1988).

  12. 12.

    T. J. Ness and G. F. Gebhart, "Characterization of neurons responsible to noxious colorectal distension in the T13-L2 spinal cord of the rat," J. Neurophysiol.,60, No. 4, 1419–1438 (1988).

  13. 13.

    R. W. Ryall and M. F. Piercy, "Visceral afferent and efferent fibers in sacral ventral roots in cats," Brain Res.,23, No. 1, 57–65 (1970).

  14. 14.

    C. J. Woolf, "A selective effect of naloxone on heterosynaptic C-fiber-mediated inhibitions in the rat dorsal horn," Neurosci. Lett.,45, No. 2, 169–174 (1984).

  15. 15.

    C. J. Woolf and P. D. Wall, "Chronic peripheral nerve section diminishes the primary afferent A-fiber mediated inhibition of rat dorsal horn neurons," Brain Res.,242, No. 1, 77–85 (1982).

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Additional information

I. M. Sechenov Medical Academy, Russian Ministry of Public Health, Moscow. Translated from Neirofiziologiya, Vol. 24, No. 1, pp. 3–11, January–February, 1992.

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Kasparov, S.A. Viscerosomatic somatic convergence at lumbar interneurons in the dorsal horn of the cat and rat spinal cord. Neurophysiology 24, 1–6 (1992). https://doi.org/10.1007/BF01053475

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Keywords

  • Spinal Cord
  • Glycine
  • Direct Effect
  • Acetylcholine
  • Atropine