Inhibitory effect of sulfur dioxide inhalation on Hering–Breuer inflation reflex in mice: role of voltage-gated potassium channels

Nai Ju Chan, Chun Chun Hsu, You Shuei Lin, Ruei Lung Lin, Lu Yuan Lee

Research output: Contribution to journalArticlepeer-review

Abstract

Slowly adapting receptors (SARs), vagal mechanosensitive receptors located in the lung, play an important role in regulating the breathing pattern and Hering–Breuer inflation reflex (HBIR). Inhalation of high concentration of sulfur dioxide (SO2), a common environmental and occupational air pollutant, has been shown to selectively block the SAR activity in rabbits, but the mechanism underlying this inhibitory effect remained a mystery. We carried out this study to determine if inhalation of SO2 can inhibit the HBIR and change the eupneic breathing pattern, and to investigate further a possible involvement of voltage-gated K+ channels in the inhibitory effect of SO2 on these vagal reflex-mediated responses. Our results showed 1) inhalation of SO2 (600 ppm; 8 min) consistently abolished both the phasic activity of SARs and their response to lung inflation in anesthetized, artificially ventilated mice, 2) inhalation of SO2 generated a distinct inhibitory effect on the HBIR and induced slow deep breathing in anesthetized, spontaneously breathing mice, and these effects were reversible and reproducible in the same animals, 3) This inhibitory effect of SO2 was blocked by pretreatment with 4-aminopyridine (4-AP), a nonselective blocker of voltage-gated K+ channel, and unaffected by pretreatment with its vehicle. In conclusion, this study suggests that this inhibitory effect on the baseline breathing pattern and the HBIR response was primarily mediated through the SO2-induced activation of voltage-gated K+ channels located in the vagal bronchopulmonary SAR neurons.

Original languageEnglish
Pages (from-to)1075-1082
Number of pages8
JournalJournal of Applied Physiology
Volume134
Issue number5
DOIs
StatePublished - May 2023

Bibliographical note

Publisher Copyright:
Copyright © 2023 the American Physiological Society.

Keywords

  • 4-aminopyridine
  • air pollutant
  • breathing pattern
  • lung
  • slowly adapting receptor
  • vagus nerve

ASJC Scopus subject areas

  • General Medicine

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