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Origin and course of crossed medullary pathways to spinal sympathetic neurons in the cat

Summary

  1. 1.

    In 12 chloralosed vagotomized cats medullary structures projecting to contralateral spinal sympathetic neurons were identified by activating fibre terminals in the intermediolateral nucleus (ILN) at functionally and histologically identified cardioacceleratory sites at the T2 level and exploring the contralateral medulla for antidromically evoked field potentials.

  2. 2.

    Evoked field potentials were recorded at 20 sites in 130 penetrations in the left medulla and at 14 sites in 70 penetrations in the right medulla; responses were recorded mainly from sites in the nucleus gigantocellularis, the nucleus paramedium reticularis and the nucleus lateralis reticularis.

  3. 3.

    In an additional 20 cats the pathways of crossed fibres from these nuclei to the ILN were identified by observing the effects on the evoked field potentials of surgical and electrolytic lesions in the medulla and spinal cord. Evoked potentials from the left nucleus gigantocellularis were abolished by a midline section in the caudal medulla, or by right medullary hemisection (5 mm caudal to the obex), or by transection of the right ventral funiculus (C6–C7). Potentials from the left nucleus paramedium reticularis were abolished by right medullary hemisection (5 mm caudal to the obex) or by transection of the right ventral funiculus (C5–C7). Potentials from the left nucleus lateralis reticularis were abolished by left spinal hemisection 2–3 mm rostral to the level of the stimulating electrode or by transection of either the left dorsolateral or the left ventral funiculus (C5–C7).

  4. 4.

    It is concluded that: a) spinal sympathetic neurons receive inputs from discrete nuclei in the contralateral medulla; b) autonomic fibres from the nucleus gigantocellularis and the nucleus paramedium reticularis to the contralateral ILN cross the midline in the caudal medulla and descend in the contralateral ventral funiculus; c) fibres from the nucleus lateralis reticularis descend in the ipsilateral dorsolateral and ventral funiculi and cross the midline in the spinal cord close to their level of termination.

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References

  1. Biscoe, T.J., Sampson, S.R.: Field potentials evoked in the brain stem of the cat by stimulation of the carotid sinus, glossopharyngeal, aortic and superior laryngeal nerves. J. Physiol. (Lond.) 209, 341–358 (1970a)

  2. Biscoe, T.J., Sampson, S.R.: Responses of cells in the brain stem of the cat to stimulation of the sinus, glossopharyngeal, aortic and superior laryngeal nerves. J. Physiol. (Lond.) 209, 359–373 (1970b)

  3. Carlsson, A., Falck, B., Fuxe, K., Hillarp, N.A.: Cellular localization of monoamines in the spinal cord. Acta physiol. scand. 60, 112–119 (1964)

  4. Chai, C.Y., Wang, S.C.: Localization of central cardiovascular mechanisms in lower brain stem of the cat. Amer. J. Physiol. 202, 25–30 (1962)

  5. Coote, J.H., MacLeod, V.H.: The possibility that noradrenaline is a sympatho-inhibitory transmitter in the spinal cord. J. Physiol. (Lond.) 255, 44P-46P (1972)

  6. Crill, W.E., Reis, D.J.: Distribution of carotid sinus and depressor nerves in cat brain stem. Amer. J. Physiol. 214, 269–276 (1968)

  7. Culberson, J.L., Kimmel, D.L.: Central distribution of primary afferent fibers of the glosso-pharyngeal and vagal nerves in the opossum, Didelphis virginiana. Brain Res. 44, 325–335 (1972)

  8. Dahlström, A., Fuxe, K.: Evidence for the existence of monoamine neurons in the central nervous system. II. Experimentally induced changes in the intraneuronal amine levels of bulbospinal neuron systems. Acta physiol. scand. 64, Suppl. 247, 7–36 (1965)

  9. Dunker, E., Rehren, D.V., Wachsmuth, D.: The vago-vagal reflex arc: some properties of its central part. Pflügers Arch. 337, 199–217 (1972)

  10. Fang, H.S., Wang, S.C.: Cardioaccelerator and cardioaugmentor points in the hypothalamus of the dog. Amer. J. Physiol. 203, 147–150 (1962)

  11. Goncharova, L.S., Stefantsov, B.D.: Bilateral representation of the vagus nerve at the level of the medulla. Neurosci. Transi. 1, 28–32 (1966)

  12. Henry, J.L., Calaresu, F.R.: Distribution of cardioacceleratory sites in intermediolateral nucleus of the cat. Amer. J. Physiol. 222, 700–704 (1972)

  13. Henry, J.L., Calaresu, F.R.: Crossed medullary input to spinal sympathetic neurons in the cat. Can. Physiol. 4, 36 (1973a)

  14. Henry, J.L., Calaresu, F.R.: Localization of excitatory and inhibitory pathways from medullary nuclei to spinal cardioacceleratory neurons in the cat. Proc. Soc. Neurosci. 330 (1973b)

  15. Henry, J.L., Calaresu, F.R.: Excitatory and inhibitory inputs from medullary nuclei projecting to spinal cardioacceleratory neurons in the cat. Exp. Brain Res. 20, 485–504 (1974)

  16. Henry, J.L., Calaresu, F.R.: Pathways from medullary nuclei to spinal cardioacceleratory neurons in the cat. Exp. Brain Res. 20, 505–514 (1974)

  17. Humphrey, D.R.: Neuronal activity in the medulla oblongata of the cat evoked by stimulation of the carotid sinus nerve. In: Baroreceptors and Hypertension, pp. 131–168. Ed. by P. Kezdi. Toronto: Pergamon Press 1967

  18. Kappagoda, C.T., Linden, R.J., Saunders, D.A.: The effect on heart rate of distending the atrial appendages in the dog. J. Physiol. (Lond.) 225, 705–719 (1972)

  19. Koss, M.C., Wang, S.C.: Brainstem loci for sympathetic activation of the nictitating membrane and pupil in the cat. Amer. J. Physiol. 222, 900–905 (1972)

  20. Kumada, M., Nakajima, H.: Field potentials evoked in rabbit brainstem by stimulation of the aortic nerve. Amer. J. Physiol. 223, 575–582 (1972)

  21. Linden, R.J., Norman, J.: The effect of acidaemia on the response to stimulation of the autonomic nerves to the heart. J. Physiol. (Lond.) 200, 51–71 (1969)

  22. Lipski, J., McAlIen, R.M., Spyer, K.M.: Localization of sinus nerve afferent endings in the brain stem. J. Physiol. (Lond.) 225, 30P-31P (1972)

  23. McQueen, D.S., Ungar, A.: On the direct and crossed components of reflex responses to unilateral stimulation of the carotid body chemoreceptors in the dog. J. Physiol. (Lond.) 219, 1–16 (1971)

  24. Merrill, E.G.: The descending pathways from the lateral respiratory neurons in cats. J. Physiol. (Lond.) 218, 82P-83P (1971)

  25. Miura, M., Reis, D.J.: Termination and secondary projections of carotid sinus nerve in the cat brain stem. Amer. J. Physiol. 217, 142–153 (1969)

  26. Mizeres, N.J.: The origin and course of the Cardioaccelerator fibres in the dog. Anat. Rec. 132, 261–280 (1958)

  27. Peiss, C.N., Randall, W.C.: Sympathetic control of the heart. In: Cardiovascular Functions, pp. 314–332. Ed. by A.A. Luisada. New York: McGraw-Hill 1962

  28. Porter, R.: Unit responses evoked in the medulla oblongata by vagus nerve stimulation. J. Physiol. (Lond.) 168, 717–735 (1963)

  29. Randall, W.C., Rohse, W.G.: The augmentor action of the sympathetic cardiac nerves. Circulat. Res. 4, 470–475 (1956)

  30. Salmoiraghi, G.C., Burns, B.D.: Notes on mechanism of rhythmic respiration. J. Neurophysiol. 23, 14–26 (1960)

  31. Wang, S.C., Ranson, S.W.: Descending pathways from the hypothalamus to the medulla and spinal cord. Observations on blood pressure and bladder responses. J. comp. Neurol. 71, 457–472 (1939)

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Henry, J.L., Calaresu, F.R. Origin and course of crossed medullary pathways to spinal sympathetic neurons in the cat. Exp Brain Res 20, 515–526 (1974). https://doi.org/10.1007/BF00238017

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Key words

  • Medulla
  • Spinal cord
  • Vasomotor centre
  • Cardiovascular control
  • Crossed autonomic pathways