Diaphragm muscle activity across respiratory motor behaviors in awake and lightly anesthetized rats

Federico Jimenez-Ruiz, Obaid U. Khurram, Wen Zhi Zhan, Heather M. Gransee, Gary C Sieck, Carlos Bernardo Mantilla

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Respiratory muscles such as the diaphragm are active across a range of behaviors including ventilation and higher-force behaviors necessary for maintenance of airway patency, and minimal information is available regarding anesthetic effects on the capacity of respiratory muscles to generate higher forces. The purpose of the present study was to determine whether diaphragm EMG activity during lower-force behaviors, such as eupnea and hypoxia-hypercapnia, is differentially affected compared with higher-force behaviors, such as a sigh, in lightly anesthetized animals. In adult male rats, chronically implanted diaphragm EMG electrodes were used to measure the effects of low-dose ketamine (30 mg/kg) and xylazine (3 mg/kg) on root mean square (RMS) EMG amplitude across a range of motor behaviors. A mixed linear model was used to evaluate the effects of ketamine-xylazine anesthesia on peak RMS EMG and ventilatory parameters, with condition (awake vs. anesthetized), behavior (eupnea, hypoxia-hypercapnia, sigh), side (left or right hemidiaphragm), and their interactions as fixed effects and animal as a random effect. Compared with the awake recordings, there was an overall reduction of peak diaphragm RMS EMG across behaviors during anesthesia, but this reduction was more pronounced during spontaneous sighs (which require 60% of maximal diaphragm force). Respiratory rates and duty cycle during eupnea and hypoxiahypercapnia were higher in awake compared with anesthetized conditions. These results highlight the importance of identifying anesthetic effects on a range of respiratory motor behaviors, including sighs necessary for maintaining airway patency. NEW & NOTEWORTHY Respiratory muscles accomplish a range of motor behaviors, with forces generated for ventilatory behaviors comprising only a small fraction of their maximal force generating capacity. Induction of anesthesia exerts more robust effects on the higher-force diaphragm motor behaviors such as sighs compared with eupnea. This novel information on effects of low, sedative doses of a commonly used anesthetic combination (ketamine-xylazine) highlights the importance of identifying anesthetic effects on a range of respiratory motor behaviors.

Original languageEnglish (US)
Pages (from-to)915-922
Number of pages8
JournalJournal of Applied Physiology
Volume124
Issue number4
DOIs
StatePublished - Apr 1 2018

Fingerprint

Diaphragm
Muscles
Xylazine
Respiratory Muscles
Anesthetics
Ketamine
Anesthesia
Hypercapnia
Respiratory Rate
Hypnotics and Sedatives
Ventilation
Linear Models
Electrodes
Maintenance

Keywords

  • Anesthesia
  • Diaphragm muscle
  • Electromyography
  • Force
  • Ketamine

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Diaphragm muscle activity across respiratory motor behaviors in awake and lightly anesthetized rats. / Jimenez-Ruiz, Federico; Khurram, Obaid U.; Zhan, Wen Zhi; Gransee, Heather M.; Sieck, Gary C; Mantilla, Carlos Bernardo.

In: Journal of Applied Physiology, Vol. 124, No. 4, 01.04.2018, p. 915-922.

Research output: Contribution to journalArticle

Jimenez-Ruiz, Federico ; Khurram, Obaid U. ; Zhan, Wen Zhi ; Gransee, Heather M. ; Sieck, Gary C ; Mantilla, Carlos Bernardo. / Diaphragm muscle activity across respiratory motor behaviors in awake and lightly anesthetized rats. In: Journal of Applied Physiology. 2018 ; Vol. 124, No. 4. pp. 915-922.
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