Inhibitory effect of gas phase cigarette smoke on breathing: role of hydroxyl radical

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Inhaling cigarette smokes evokes immediate bradypnea in rats, resulting from stimulation of vagal bronchopulmonary C-fiber afferents by smoke constituent(s) other than nicotine. To determine the contribution of the gas phase of smoke to this irritant effect, the acute respiratory responses to both cigarette smoke and gas phase smoke were studied and compared in anesthetized Sprague-Dawley rats; smoke (6 ml, 50%) was generated by a machine from low-nicotine research cigarettes and the gas phase was obtained by passing the smoke through a glass-fiber Cambridge filter. Inhalation of gas phase smoke alone evoked a transient inhibitory effect on breathing, prolonging expiratory time (Te) to peak of 159 ± 6% of the base line; this response was very similar to that triggered by inhaling the unified smoke (Te = 177 ± 12%). The bradypnea started within 1-4 breaths after the onset of smoke inhalation, lasted for 3-5 breaths and was completely abolished by vagotomy. This inhibitory effect of gas phase smoke on breathing was also largely prevented after a pretreatment with either intravenous infusion or aerosol inhalation of hydroxyl radical scavenger, dimethylthiourea. These results suggest that the gas phase is primarily responsible for eliciting the reflexogenic bradypneic response to cigarette smoke in anesthetized rats and that hydroxyl radicals released endogenously in the lungs may be involved.

Original languageEnglish
Pages (from-to)227-238
Number of pages12
JournalRespiration Physiology
Issue number2
StatePublished - Nov 1990

Bibliographical note

Funding Information:
assistance, and to John Turbek for statistical analysis of the data. This study was supported by Program Project Grant HL-40369 from the National Heart, Lung and Blood Institute, and by University of Kentucky Tobacco and Health Research Institute Grant 41066.


  • Airway receptors
  • Animal
  • Bronchopulmonary afferents
  • Cigarette smoke
  • Drugs
  • Oxygen radicals
  • airway receptors
  • cigarette smoke
  • dimethylthiourea
  • rat
  • response to smoke

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine


Dive into the research topics of 'Inhibitory effect of gas phase cigarette smoke on breathing: role of hydroxyl radical'. Together they form a unique fingerprint.

Cite this