The Journal of Physiological Sciences

, Volume 69, Issue 6, pp 961–968 | Cite as

Firing properties of medullary expiratory neurons during fictive straining in cats

  • Sei-Ichi Sasaki
  • Ken Muramatsu
  • Masatoshi NiwaEmail author
Original Paper


Expiratory (E) neurons in the caudal nucleus retroambigualis extend descending spinal axons to the lumbar and sacral spinal cord. Discharge rates of single E neurons were recorded to examine differences in activity of E neurons projecting to the lumbar or sacral spinal cord during fictive straining induced by distention of the colon with a balloon. Firing frequencies of E neurons with descending axons in the thoracic and lumbar spinal cord increased during the repetitive rise of rectum pressure, whereas those of E neurons with descending axons in the sacral spinal cord decreased. E neurons with descending axons in the thoracic/lumbar and sacral spinal cord exhibit different firing characteristics during the repetitive rise of rectum pressure when straining during defecation. The activity of abdominal nerves during fictive straining is in phase with changes in rectum pressure, but out of phase with the activity of E neurons.


Brainstem Expiratory neuron Spinal cord Straining 



We would like to thank Editage ( for English language editing.

Author contributions

All co-authors participated in data collection and analysis. All co-authors have read and approved the final manuscript.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All experimental procedures were approved by the Animal Ethics Committee of Ibaraki Prefectural University of Health Sciences and were in accordance with the guiding principles for care and use of animals in the field of physiological sciences outlined by the Physiological Society of Japan.


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Copyright information

© The Physiological Society of Japan and Springer Japan KK, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Center for Medical SciencesIbaraki Prefectural University of Health SciencesIbarakiJapan
  2. 2.Department of Physical TherapyKyorin UniversityTokyoJapan
  3. 3.Department of Occupational TherapyKyorin UniversityMitakaJapan
  4. 4.Toyo Public Health CollegeTokyoJapan

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