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. 1973 Aug;233(1):45–62. doi: 10.1113/jphysiol.1973.sp010296

Extra-segmental reflexes derived from intercostal afferents: phrenic and laryngeal responses

John E Remmers
PMCID: PMC1350538  PMID: 4759121

Abstract

1. Phrenic and recurrent laryngeal efferent responses were evoked by brief tetani or single shocks to the cut external intercostal nerves of anaesthetized cats. The reflexes derived from middle thoracic segments (T5 and 6) were compared with those emanating from caudal thoracic segments (T9 and 10).

2. During inspiration, middle intercostal nerve stimulation transiently inhibited the spontaneous discharge in both efferent neurograms, whereas stimulation of caudal intercostal nerves facilitated phrenic discharge and usually inhibited recurrent laryngeal activity.

3. During expiration, stimulation at either thoracic level enhanced recurrent laryngeal discharge while provoking little or no phrenic response.

4. Superficial lesions of the lateral cervical cord, ipsilateral to the stimulus sites, above or below the phrenic outflow, eliminated all reflex responses except the phrenic response to caudal thoracic stimuli. Similarly, in the spinal animal, middle intercostal afferents could not be shown to decrease phrenic excitability. Caudal intercostal afferents cause phrenic excitation by a spinal reflex.

5. Group I afferents of the mid-thoracic segments and group II afferents of the caudal thoracic segments initiate these extra-segmental reflexes.

6. The recurrent laryngeal responses manifest, for the most part, changes in the discharge of fibres innervating the posterior cricoarytenoid muscle. The responses fit the overall pattern of response to middle intercostal nerve stimulation, namely, inhibition of inspiratory muscles and excitation of expiratory muscles. Intercostal afferent stimulation also activated the laryngeal adductor muscles.

7. The results support the view that intercostal mechanoreceptors initiate an array of extra-segmental respiratory reflexes, including spinal and supraspinal arcs. The simplest way to account for the various responses to stimulation of middle intercostal afferents is to postulate a reflex involving supraspinal respiratory neurones.

8. The observed reflexogenic differences correlate with anatomical differences between the middle and caudal ribs. Possible functional implications of this relationship are discussed.

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Selected References

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

  1. Biscoe T. J., Sampson S. R. An analysis of the inhibition of phrenic motoneurones which occurs on stimulation of some cranial nerve afferents. J Physiol. 1970 Aug;209(2):375–393. doi: 10.1113/jphysiol.1970.sp009170. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. CALMA I. The reflex activity of the respiratory centre. J Physiol. 1952 May;117(1):9–21. [PMC free article] [PubMed] [Google Scholar]
  3. CRITCHLOW V., VON EULER INTERCOSTAL MUSCLE SPINDLE ACTIVITY AND ITS GAMMA MOTOR CONTROL. J Physiol. 1963 Oct;168:820–847. doi: 10.1113/jphysiol.1963.sp007225. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Coffey G. L., Godwin-Austen R. B., Macgillivray B. B., Sears T. A. The form and distribution of the surface evoked responses in cerebellar cortex from intercostal nerves in the cat. J Physiol. 1971 Jan;212(1):129–145. doi: 10.1113/jphysiol.1971.sp009314. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. DOWNMAN C. B., HUSSAIN A. Spinal tracts and supraspinal centres influencing visceromotor and allied reflexes in cats. J Physiol. 1958 May 28;141(3):489–499. doi: 10.1113/jphysiol.1958.sp005990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. DOWNMAN C. B. Skeletal muscle reflexes of splanchnic and intercostal nerve origin in acute spinal and decerebrate cats. J Neurophysiol. 1955 May;18(3):217–235. doi: 10.1152/jn.1955.18.3.217. [DOI] [PubMed] [Google Scholar]
  7. Davis J. N., Plum F. Separation of descending spinal pathways to respiratory motoneurons. Exp Neurol. 1972 Jan;34(1):78–94. doi: 10.1016/0014-4886(72)90189-6. [DOI] [PubMed] [Google Scholar]
  8. Decima E. E., von Euler C. Excitability of phrenic motoneurones to afferent input from lower intercostal nerves in the spinal cat. Acta Physiol Scand. 1969 Apr;75(4):580–591. doi: 10.1111/j.1748-1716.1969.tb04413.x. [DOI] [PubMed] [Google Scholar]
  9. Decima E. E., von Euler C. Intercostal and cerebellar influences on efferent phrenic activity in the decerebrate cat. Acta Physiol Scand. 1969 May-Jun;76(1):148–158. doi: 10.1111/j.1748-1716.1969.tb04459.x. [DOI] [PubMed] [Google Scholar]
  10. Decima E. E., von Euler C., Thoden U. Intercostal-to-phrenic reflexes in the spinal cat. Acta Physiol Scand. 1969 Apr;75(4):568–579. [PubMed] [Google Scholar]
  11. GARCIA RAMOS J., LOPEZ MENDOZA E. On the integration of respiratory movements. II. The integration at spinal level. Acta Physiol Lat Am. 1959;9:257–266. [PubMed] [Google Scholar]
  12. GARCIA RAMOS J. On the integration of respiratory movements. I. Acta Physiol Lat Am. 1959;9:246–256. [PubMed] [Google Scholar]
  13. Irani B., Megirian D., Sherrey J. H. An analysis of reflex changes in excitability of phrenic, laryngeal, and intercostal motoneurons. Exp Neurol. 1972 Jul;36(1):1–13. doi: 10.1016/0014-4886(72)90131-8. [DOI] [PubMed] [Google Scholar]
  14. Kurozumi S., Tashiro T., Harada Y. Laryngeal responses to electrical stimulation of the medullary respiratory centers in the dog. Laryngoscope. 1971 Dec;81(12):1960–1967. doi: 10.1002/lary.5540811208. [DOI] [PubMed] [Google Scholar]
  15. Megirian D. Vestibular control of laryngeal and phrenic motoneurons of cat. Arch Ital Biol. 1968 Dec;106(4):333–342. [PubMed] [Google Scholar]
  16. Murakami Y., Kirchner J. A. Respiratory movements of the vocal cords. An electromyographic study in the cat. Laryngoscope. 1972 Mar;82(3):454–467. doi: 10.1288/00005537-197203000-00015. [DOI] [PubMed] [Google Scholar]
  17. NAKAMURA F., UYEDA Y., SONODA Y. Electromyographic study on respiratory movements of the intrinsic laryngeal muscles. Laryngoscope. 1958 Feb;68(2):109–119. doi: 10.1288/00005537-195802000-00002. [DOI] [PubMed] [Google Scholar]
  18. NAKAYAMA S., VON BAUMGARTEN LOKALISIERUNG ABSTEIGENDER ATMUNGSBAHNEN IM RUECKENMARK DER KATZE MITTELS ANTIDROMER REIZUNG. Pflugers Arch Gesamte Physiol Menschen Tiere. 1964 Oct 22;281:231–244. doi: 10.1007/BF00412424. [DOI] [PubMed] [Google Scholar]
  19. Remmers J. E. Inhibition of inspiratory activity by intercostal muscle afferents. Respir Physiol. 1970 Oct;10(3):358–383. doi: 10.1016/0034-5687(70)90055-1. [DOI] [PubMed] [Google Scholar]
  20. Remmers J. E., Tsiaras W. G. Effect of lateral cervical cord lesions on the respiratory rhythm of anaesthetized, decerebrate cats after vagotomy. J Physiol. 1973 Aug;233(1):63–74. doi: 10.1113/jphysiol.1973.sp010297. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. SEARS T. A. Activity of fusimotor fibres innervating muscle spindles in the intercostal muscles of the cat. Nature. 1963 Mar 9;197:1013–1014. doi: 10.1038/1971013a0. [DOI] [PubMed] [Google Scholar]
  22. SEARS T. A. EFFERENT DISCHARGES IN ALPHA AND FUSIMOTOR FIBRES OF INTERCOSTAL NERVES OF THE CAT. J Physiol. 1964 Nov;174:295–315. doi: 10.1113/jphysiol.1964.sp007488. [DOI] [PMC free article] [PubMed] [Google Scholar]

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