title: The effect of angiotensin-converting enzyme inhibition by captopril on respiratory mechanics in healthy rats.
abstract: BACKGROUND
  Angiotensin stimulates smooth-muscle contraction. Accordingly, angiotensin-converting enzyme (ACE) inhibition is expected to decrease airway resistance.
  
  
  OBJECTIVE
  To measure the effects of ACE inhibition on respiratory mechanics in healthy mammals.
  
  
  METHODS
  We measured respiratory mechanics before and after i.p. ACE inhibitor captopril (100 mg/kg) in normal anaesthetised rats. The end-inflation occlusion method allowed the measurements of respiratory system elastance and ohmic and viscoelastic pressure dissipations. Respiratory system hysteresis and the elastic and resistive work of breathing were calculated.
  
  
  RESULTS
  Captopril induced a reduction of the ohmic and the total respiratory system resistances, while respiratory system hysteresis and elastance did not change. Accordingly, a reduction of the resistive and of the total work of breathing was observed.
  
  
  CONCLUSIONS
  The captopril-induced reduction of airway resistance indicates that angiotensin modulates bronchomotor tone in basal conditions. ACE inhibition may positively affect respiratory system mechanics and work of breathing.
authors.affiliation: Department of Human Anatomy and Physiology, Section Physiology, University of Padova, Via Marzolo, Padova, Italy. alessandro.rubini@unipd.it
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rubini
authors.forename: Marco
authors.initials: M
authors.lastname: Redaelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Parmagnani
mesh_terms: D000403:Airway Resistance / Q000187:drug effects*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology*; D005260:Female; D007274:Injections, Intraperitoneal; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012119:Respiration / Q000187:drug effects; D015656:Respiratory Mechanics / Q000187:drug effects*; D012137:Respiratory System / Q000187:drug effects
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D002216:Captopril