Reflex tracheal contraction induced by stimulation of bronchial C-fibers in dogs

A. M. Roberts, Marc P Kaufman, D. G. Baker, J. K. Brown, H. M. Coleridge, J. C. Coleridge

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

Bradykinin stimulates the afferent vagal endings of bronchial C-fibers but has little effect on other pulmonary vagal afferents. In anesthetized dogs with open chest, we recorded transverse tension in the posterior wall (trachealis muscle) of an upper cervical tracheal segment and stimulated bronchial C-fibers selectively by injecting bradykinin (19 ng-3 μg) into a bronchial artery. The recurrent and pararecurrent laryngeal nerves were cut so that the superior laryngeal nerves provided the motor supply to the segment. Bradykinin caused a dose-dependent increase in tracheal muscle tension and often a conspicuous decrease in heart rate, which were abolished by vagotomy or administration of atropine. Injection of bradykinin still evoked tracheal contraction when myelinated lung afferents were blocked by cooling the midcervical vagi to 7°C, but contraction was abolished when unmyelinated lung afferents were blocked by cooling to 0-1°C, the effects of cooling being reversible. Our results indicate that stimulation of bronchial C-fibers, like that of pulmonary C-fibers, evokes reflex contraction of airway smooth muscle and reflex cardiac slowing.

Original languageEnglish (US)
Pages (from-to)485-493
Number of pages9
JournalJournal of Applied Physiology Respiratory Environmental and Exercise Physiology
Volume51
Issue number2
StatePublished - 1981
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Endocrinology

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