Stimulation of groups III and IV phrenic afferents reflexly decreases total lung resistance in dogs

L. W. McCallister, K. W. McCoy, J. C. Connelly, Marc Kaufman

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Little is known about the reflex effect on airway caliber evoked by stimulation of phrenic afferents. Therefore, in chloralose-anesthetized, paralyzed dogs, we recorded airflow, airway pressure, arterial pressure, and heart rate while electrically stimulating a phrenic nerve. Total lung resistance was calculated breath by breath. The phrenic nerve was stimulated at 3, 5, 20, 70, 140, and 200 times motor threshold and the compound action potential was recorded. Stimulation of the phrenic nerve at three and five times threshold, which activated groups I, II, and a few group III fibers, had no effect on any of the variables measured. Stimulation at 20 times threshold, which activated many group III fibers and groups I and II fibers, reflexly decreased resistance. Stimulation at 70, 140, and 200 times threshold, which activated groups I-IV fibers, evoked progressively greater decreases in lung resistance. The reflex bronchodilation evoked by phrenic nerve stimulation was unaffected by propranolol or phentolamine but was abolished by atropine. We conclude that activation of groups III and IV phrenic nerve afferents reflexly decreased total lung resistance by withdrawing cholinergic tone to airway smooth muscle.

Original languageEnglish (US)
Pages (from-to)1345-1351
Number of pages7
JournalJournal of applied physiology
Volume61
Issue number4
DOIs
StatePublished - 1986

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Fingerprint Dive into the research topics of 'Stimulation of groups III and IV phrenic afferents reflexly decreases total lung resistance in dogs'. Together they form a unique fingerprint.

  • Cite this