Pulmonary vagal reflexes and breathing pattern are not altered in elastase-induced emphysema in rats.
The role of nonmyelinated and myelinated vagal afferents in pulmonary reflexes and breathing pattern was examined in elastase-treated emphysemic rats. Fourteen to 17 days after intratracheal instillation of 1 IU/gm of porcine pancreatic elastase or 0.5 mL of saline, elastase-treated rats had a decreased alveolar surface area to volume of parenchyma (Sv) (42.44 +/- 1.7 vs. 31.51 +/- 1.1 mm2/mm3), increased quasistatic compliance (QSC) (1.05 +/- 0.06 vs. 1.25 +/- 0.09 mL/cm H2O), functional residual capacity (FRC) (4.31 +/- 0.10 vs. 5.88 +/- 0.37 mL), residual volume (RV) (3.02 +/- 0.14 vs. 4.27 +/- 0.31 mL), and total lung capacity (TLC) (14.04 +/- 0.28 vs. 15.58 +/- 0.54 mL). There were no changes in the strength of the pulmonary chemoreflex, the strength of the Hering-Breuer inflation reflex, or breathing pattern before or after vagal perineural capsaicin treatment (VPCT) or vagotomy. There were, however, significant negative correlations between Sv and TLC, FRC and RV, and a near significant (p < .09) negative correlation between Sv and QSC, but no significant correlations between Sv and indices of either the pulmonary chemoreflex or Hering-Breuer inflation reflex. The results indicate that pulmonary vagal nonmyelinated and myelinated reflex activity and breathing pattern are not affected by elastase-induced emphysema in rats.
Mansoor
J K
JK
Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California-Davis 95616, USA. jkmansoor@ucdavis.edu
Hyde
D M
DM
Schelegie
E S
ES
D000818:Animals; D002245:Carbon Dioxide / Q000097:blood; D004195:Disease Models, Animal; D004646:Emphysema / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology*; D006863:Hydrogen-Ion Concentration; D008168:Lung / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology; D010100:Oxygen / Q000097:blood; D010196:Pancreatic Elastase / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000187:drug effects / Q000502:physiology; D012119:Respiration / Q000502:physiology*; D014628:Vagotomy; D014630:Vagus Nerve / Q000503:physiopathology*
D002245:Carbon Dioxide; D010196:Pancreatic Elastase; D010100:Oxygen