Reflex apneic response evoked by laryngeal exposure to wood smoke in rats: Neural and chemical mechanisms

Y. S. Lin, Y. R. Kou

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We investigated the neural and chemical mechanisms contributing to the immediate ventilatory responses to laryngeal exposure to wood smoke in anesthetized Sprague-Dawley rats. Five milliliters of wood smoke were delivered into a functionally isolated larynx at a constant flow rate of 1.4 ml/s while the animals breathed spontaneously. Within 1 s after exposure, laryngeal wood smoke consistently triggered an apnea in each of the 42 rats tested. The apneic duration reached 1,636.4 ± 105.4 (SE) % (n = 42) of the baseline expiratory duration. This apneic response was not affected by denervation of recurrent laryngeal nerves (n = 6) or by removal of smoke particulates (n = 14), but it was totally eliminated by topical application of an anesthetic (n = 8; lidocaine hydrochloride, 8%) to the laryngeal mucosa or by sectioning of the superior laryngeal nerves (n = 42). Furthermore, laryngeal application of a hydroxyl radical scavenger (dimethylthiourea; 500 mg/ml; n = 8) greatly diminished or abolished the smoke-induced apneic response, but it did not affect the apneic response evoked by laryngeal exposure to air saturated with 6% ammonia. These results suggest that the immediate apneic response to laryngeal wood smoke is a reflex resulting from the stimulation of the superior laryngeal afferents by the gas phase of wood smoke and that the stimulation is mediated through a hydroxyl radical mechanism.

Original languageEnglish
Pages (from-to)723-730
Number of pages8
JournalJournal of Applied Physiology
Volume83
Issue number3
Publication statusPublished - Sep 1997
Externally publishedYes

Fingerprint

Smoke
Reflex
Hydroxyl Radical
Laryngeal Mucosa
Laryngeal Nerves
Recurrent Laryngeal Nerve
Denervation
Apnea
Larynx
Lidocaine
Local Anesthetics
Ammonia
Sprague Dawley Rats
Gases
Air

Keywords

  • Ammonia
  • Dimethylthiourea
  • Gas phase
  • Hydroxyl radicals
  • Laryngeal irritation
  • Particulates

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Reflex apneic response evoked by laryngeal exposure to wood smoke in rats : Neural and chemical mechanisms. / Lin, Y. S.; Kou, Y. R.

In: Journal of Applied Physiology, Vol. 83, No. 3, 09.1997, p. 723-730.

Research output: Contribution to journalArticle

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