Breathing frequency responses to pulmonary CO2 in an isolated lobe of the canine lung. J Appl Physiol Respir Environ Exerc Physiol 1979 Dec;47(6):1201-6
Date
12/01/1979Pubmed ID
536290DOI
10.1152/jappl.1979.47.6.1201Scopus ID
2-s2.0-0018577317 (requires institutional sign-in at Scopus site) 7 CitationsAbstract
Recent studies have indicated that the breathing frequency responses to inspired CO2 in part result from changes in pulmonary stretch receptor activity. Pulmonary CO2 may alter frequency by direct inhibition of stretch receptor discharge, or secondarily, by changes in airway mechanics. The vascularly isolated left lower lobe (LLL) of the canine lung was used to determine the effect of hypocapnic airway constriction on the pulmonary CO2 reflex. The upper and middle lobes of the left lung were removed and the right vagus nerve sectioned. Blood was recirculated through the LLL. Diaphragm electromyogram was used as an index of respiratory center activity and to trigger ventilation of the left lower lobe. Lobar hypocapnia increased peak airway pressure and reduced respiratory rate. However, infusion of isoproterenol or the use of a mechanical overflow system to block the airway pressure response prevented the frequency changes associated with CO2. Although both the direct and mechanical effects of CO2 on stretch receptors may contribute to the reflex, in the LLL preparation the mechanical effects predominate.
Author List
Nilsestuen JO, Coon RL, Igler FO, Zuperku EJ, Kampine JPAuthor
Edward J. Zuperku PhD, MS Emeritus Professor in the Anesthesiology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Airway ResistanceAnimals
Biomechanical Phenomena
Carbon Dioxide
Dogs
Feedback
Lung
Lung Compliance
Mechanoreceptors
Reflex
Respiration
Vagus Nerve
