Lower Lumbar and Sacral Projections of Caudal Medullary Expiratory Neurons in the Cat

  • Sei-Ichi Sasaki
  • Hiroyuki Uchino
  • Yoshio Uchino


Respiratory rhythmogenesi’s is organized in the brain stem and respiratory rhythm is then transmitted to the spinal respiratory motoneurons. Expiratory (E) neurons in the caudal nucleus retroambigualis are bulbospinal neurons1 and have axonal branches in the thoracic and the upper lumbar spinal cord2, 3, 4. E neurons exert synaptic effects to the internal intercostal and the abdominal motoneurons monosynaptically and/or via interneurons3, 5, 6. Recently, the autoradiographic tracing method have revealed a projection from the region of the nucleus retroambigualis to the nucleus of Onuf in the sacral spinal cord. In the present experiments, we have examined the lower lumbar (L6–L7) and sacral (S1–S3) spinal projections of physiological identified caudal medullary expiratory neurons.


Phrenic Nerve Spinal Projection Lumbar Spinal Cord2 Lower Lumbar Antidromic Activation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    H. Arita, N. Kogo, and N. Koshiya, Morphological and physiological properties of caudal medullary expiratory neurons of the cat, Brain Res. 401:258–266(1987).PubMedCrossRefGoogle Scholar
  2. 2.
    E.G. Merrill, and J. Lipski, Inputs to intercostal motoneurons from ventrolateral medullary respiratory neurons in the cat, J. Neurophysiol. 57:1837–1853(1987).PubMedGoogle Scholar
  3. 3.
    A.D. Miller, K. Ezure, and I. Suzuki, Control of abdominal muscles by brain stem respiratory neurons in the cat, J. Neurophysiol. 54:155–167(1985).PubMedGoogle Scholar
  4. 4.
    S.-I. Sasaki, H. Uchino, M. Imagawa, T. Miyake, and Y. Uchino, Lumbar and sacral spinal projection of medullary expiratory neurons in the cat, Jap. J. Physiol. 40:Suppl. S49(1990).Google Scholar
  5. 5.
    M.I. Cohen, J.L. Feldman, and D. Sommer, Caudal medullary expiratory neurone and internal intercostal nerve discharges in the cat:effects of lung inflation, J. Physiol. 368:147–178(1985).PubMedGoogle Scholar
  6. 6.
    P.A. Kirkwood, and T.A. Sears, Monosynaptic excitation of thoracic motoneurones from lateral respiratory neurones in the medulla of the cat, J. Physiol. 234:87–89P(1973).Google Scholar
  7. 7.
    G. Holstege, and J. Tan, Supraspinal control of motoneurons innervating the striated muscles of the pelvic floor including urethral and anal sphincters in the cat, Brain. 110:1323–1344(1987).PubMedCrossRefGoogle Scholar
  8. 8.
    A.D. Miller, Localization of motoneurons innervating individual abdominal muscles of the cat, J. Comp. Neurol. 256:600–606(1987).PubMedCrossRefGoogle Scholar
  9. 9.
    S.-I. Sasaki, H. Uchino, M. Imagawa, T. Miyake, and Y. Uchino, Lower lumbar branching of caudal medullary expiratory neurons in the cat, Brain Res. 553:159–162(1991).PubMedCrossRefGoogle Scholar
  10. 10.
    B. Bishop, Reflex control of abdominal muscles during positive-pressure breathing, J. Appl. Physiol. 19:224–232(1964).PubMedGoogle Scholar
  11. 11.
    S.-I. Sasaki, K. Yokogushi, and M. Aoki, Synaptic events in cat abdominal motoneurons during respiration, Neurosci. Res. Suppi. 9:S90(1989).CrossRefGoogle Scholar
  12. 12.
    B. Onuf, On the arrangement and function of the cell groups of the sacral region of the spinal cord in man, Arch. Neurol. Psychopathol. 3:387–412(1900).Google Scholar
  13. 13.
    T. Ueyama, N. Mizuno, S. Nomura, A. Konishi, K. Itoh, and H. Arakawa, Central distribution of afferent and efferent components of the pudendal nerve in cat, J. Comp. Neurol. 222:38–46(1984).PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1992

Authors and Affiliations

  • Sei-Ichi Sasaki
    • 1
  • Hiroyuki Uchino
    • 2
  • Yoshio Uchino
    • 1
  1. 1.Department of PhysiologyTokyo Medical CollegeTokyoJapan
  2. 2.Department of AnesthesiologyTokyo Medical CollegeTokyo 160Japan

Personalised recommendations