title: Angiotensin-converting enzyme inhibitors, inhibition of brain and peripheral angiotensin-converting enzymes, and left ventricular dysfunction in rats after myocardial infarction.
abstract: BACKGROUND
  The brain renin-angiotensin system contributes significantly to progressive left ventricular (LV) dysfunction in rats after myocardial infarction (MI). The present study evaluated the effects of central versus peripheral plus central angiotensin-converting enzyme (ACE) blockade on sympathetic activity, and LV anatomy and function after MI.
  
  
  METHODS
  Wistar rats were treated for 4 weeks after MI with the lipophilic ACE inhibitor trandolapril at 5 mg/kg/day or the hydrophilic blocker lisinopril at 50 mg/kg/day by once daily subcutaneous injection, or with a central infusion of lisinopril at 0.1 mg/kg/day.
  
  
  RESULTS
  At 24 hours after the last dose, subcutaneous trandolapril caused 70% to 80% ACE inhibition in both brain and kidneys; lisinopril caused 10% to 20% less. Central infusion of lisinopril caused 70% inhibition of brain ACE and minimal (6%) inhibition in the kidneys. All three treatments similarly improved sympathetic reactivity and arterial baroreflex function. All three treatments lowered cardiac Ang I and II, and similarly attenuated the increases in LV end diastolic pressure, circumference, and fibrosis. Both subcutaneous treatments further decreased LV peak systolic pressure and dP/dt max, whereas icv lisinopril caused no change.
  
  
  CONCLUSIONS
  Despite marked differences in the extent of peripheral blockade, all three treatments similarly affected sympathetic activity and decreased cardiac Ang II, preload and remodeling after MI. One may speculate that central and peripheral ACE-mediated mechanisms are sequential and therefore only minor additional effects of peripheral ACE blockade are noted.
authors.affiliation: Hypertension Unit, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
authors.forename: Monir
authors.initials: M
authors.lastname: Ahmad
authors.forename: Roselyn
authors.initials: R
authors.lastname: White
authors.forename: Junhui
authors.initials: J
authors.lastname: Tan
authors.forename: Bing S
authors.initials: BS
authors.lastname: Huang
authors.forename: Frans H H
authors.initials: FH
authors.lastname: Leenen
mesh_terms: D000803:Angiotensin I / Q000378:metabolism; D000804:Angiotensin II / Q000378:metabolism; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D017704:Baroreflex / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000201:enzymology; D005355:Fibrosis; D006439:Hemodynamics; D007211:Indoles / Q000008:administration & dosage / Q000494:pharmacology*; D007262:Infusions, Intravenous; D007279:Injections, Subcutaneous; D007668:Kidney / Q000187:drug effects / Q000201:enzymology; D017706:Lisinopril / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009203:Myocardial Infarction / Q000150:complications* / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012084:Renin-Angiotensin System / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007211:Indoles; D000804:Angiotensin II; C052035:trandolapril; D000803:Angiotensin I; D017706:Lisinopril