Electrical activation of expiratory muscles increases with time in pentobarbital-anesthetized dogs

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Although the pentobarbital-anesthetized dog is often used as a model in studies of respiratory muscle activity during spontaneous breathing, there is no information regarding the stability of the pattern of breathing of this model over time. The electromyograms of several inspiratory and expiratory muscle groups were measured in six dogs over a 4-h period by use of chronically implanted electrodes. Anesthesia was induced with pentobarbital sodium (25 mg/kg iv), with supplemental doses to maintain constant plasma pentobarbital concentrations. Phasic electrical activity increased over time in the triangularis sterni, transversus abdominis, and external oblique muscles (expiratory muscles). The electrical activity of the costal diaphragm, crural diaphragm, and parasternal intercostal muscles (inspiratory muscles) was unchanged. These changes in electrical activity occurred despite stable plasma levels of pentobarbital and arterial PCO2. They were associated with changes in chest wall motion and an increased tidal volume with unchanged breathing frequency. We conclude that expiratory muscle groups are selectively activated with time in pentobarbital-anesthetized dogs lying supine. Therefore the duration of anesthesia is an important variable in studies using this model.

Original languageEnglish (US)
Pages (from-to)2285-2291
Number of pages7
JournalJournal of applied physiology
Issue number6
StatePublished - 1992


  • diaphragm
  • expiratory muscle activity
  • external oblique
  • inspiratory muscle activity
  • parasternal intercostals
  • time effects of anesthesia
  • transversus abdominis
  • triangularis sterni

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


Dive into the research topics of 'Electrical activation of expiratory muscles increases with time in pentobarbital-anesthetized dogs'. Together they form a unique fingerprint.

Cite this