title: The effect of chronic L-arginine administration on vascular recovery following cold cardioplegic arrest in rats.
abstract: OBJECTIVE
  Acute administration of L-arginine (LA), the physiological substrate of nitric oxide, has been used as a strategy for myocardial protection during ischemia-reperfusion. The aim of this study was to assess the effects of chronic oral LA administration on vascular functions and morphology after prolonged cold cardioplegic arrest.
  
  
  METHODS
  Adult male Sprague-Dawley rats (600-650 g) were divided into control and LA groups, which received LA (4 mg/ml) for 6 weeks. Two experimental protocols were carried out. (1) Isolated rat heart perfusion was performed and hearts were subjected to ischemia for 4 h at 4 degrees C using cold crystalloid cardioplegia (n=8 in LA, n=7 in control). Endothelial and vascular smooth muscle functions were assessed through observations of pre- and post-ischemic coronary flow response to 5-hydroxytryptamine (5-HT) and glyceryl trinitrate (GTN) (%5-HT and %GTN, respectively). (2) Semi-quantitative assessment of tissue morphology was conducted after the same ischemia-reperfusion protocol (n=4 in each group).
  
  
  RESULTS
  The LA group showed significantly better recovery (post-/pre-ischemic value) of %5-HT (97.0+/-65.6 versus 21.5+/-25.7%, P=0.015) and %GTN (124.5+/-117.6 versus 47.7+/-16.6%, P=0.021). The histological assessment showed no significant differences between the two groups.
  
  
  CONCLUSIONS
  Chronic oral administration of LA significantly ameliorated the postischemic recovery of endothelial and vascular smooth muscle functions after cold cardioplegic arrest in rats.
authors.affiliation: National Heart and Lung Institute Heart Science Centre, Harefield Hospital, Harefield, Middlesex UB9 6JH, UK.
authors.forename: Koki
authors.initials: K
authors.lastname: Nakamura
authors.forename: Ilona
authors.initials: I
authors.lastname: Schmidt
authors.forename: Caroline C
authors.initials: CC
authors.lastname: Gray
authors.forename: Ann
authors.initials: A
authors.lastname: Dewar
authors.forename: Steve
authors.initials: S
authors.lastname: Rothery
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Severs
authors.forename: Magdi H
authors.initials: MH
authors.lastname: Yacoub
authors.forename: Mohamed
authors.initials: M
authors.lastname: Amrani
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001120:Arginine / Q000008:administration & dosage* / Q000097:blood; D003080:Cold Temperature; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006324:Heart Arrest, Induced; D007036:Hypothermia, Induced; D008297:Male; D023421:Models, Animal; D008955:Models, Cardiovascular; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000097:blood; D005996:Nitroglycerin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology; D013997:Time Factors; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D016166:Free Radical Scavengers; D014665:Vasodilator Agents; D009569:Nitric Oxide; D012701:Serotonin; D001120:Arginine; D005996:Nitroglycerin