title: Sarcoplasmic phospholamban protein is involved in the mechanisms of postresuscitation myocardial dysfunction and the cardioprotective effect of nitrite during resuscitation.
abstract: OBJECTIVE
  Sarcoplasmic reticulum (SR) Ca(2+)-handling proteins play an important role in myocardial dysfunction after acute ischemia/reperfusion injury. We hypothesized that nitrite would improve postresuscitation myocardial dysfunction by increasing nitric oxide (NO) generation and that the mechanism of this protection is related to the modulation of SR Ca(2+)-handling proteins.
  
  
  METHODS
  We conducted a randomized prospective animal study using male Sprague-Dawley rats. Cardiac arrest was induced by intravenous bolus of potassium chloride (40 µg/g). Nitrite (1.2 nmol/g) or placebo was administered when chest compression was started. No cardiac arrest was induced in the sham group. Hemodynamic parameters were monitored invasively for 90 minutes after the return of spontaneous circulation (ROSC). Echocardiogram was performed to evaluate cardiac function. Myocardial samples were harvested 5 minutes and 1 hour after ROSC.
  
  
  RESULTS
  Myocardial function was significantly impaired in the nitrite and placebo groups after resuscitation, whereas cardiac function (i.e., ejection fraction and fractional shortening) was significantly greater in the nitrite group than in the placebo group. Nitrite administration increased the level of nitric oxide in the myocardium 5 min after resuscitation compared to the other two groups. The levels of phosphorylated phospholamban (PLB) were decreased after resuscitation, and nitrite increased the phosphorylation of phospholamban compared to the placebo. No significant differences were found in the expression of sarcoplasmic reticulum Ca(2+) ATPase (SERCA2a) and ryanodine receptors (RyRs).
  
  
  CONCLUSIONS
  postresuscitation myocardial dysfunction is associated with the impairment of PLB phosphorylation. Nitrite administered during resuscitation improves postresuscitation myocardial dysfunction by preserving phosphorylated PLB protein during resuscitation.
authors.affiliation: The Third People's Hospital of Chengdu, The Second Affiliated Hospital of Chengdu, Chongqing Medical University, Chengdu, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Huang
authors.affiliation: The Third People's Hospital of Chengdu, The Second Affiliated Hospital of Chengdu, Chongqing Medical University, Chengdu, China ; Department of Respiratory Disease, West China Hospital of Sichuan University, Chengdu, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: He
authors.affiliation: Department of Respiratory Disease, West China Hospital of Sichuan University, Chengdu, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhan
authors.affiliation: Department of Respiratory Disease, West China Hospital of Sichuan University, Chengdu, China ; Department of Intensive Care Unit, The Second Hospital of Anhui Medical University, Anhui, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D006321:Heart / Q000187:drug effects / Q000502:physiology; D006323:Heart Arrest / Q000139:chemically induced / Q000378:metabolism; D006333:Heart Failure / Q000188:drug therapy / Q000378:metabolism*; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009573:Nitrites / Q000627:therapeutic use*; D010766:Phosphorylation; D020011:Protective Agents / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012151:Resuscitation; D012519:Sarcoplasmic Reticulum / Q000378:metabolism / Q000502:physiology*; D000099211:Phospholamban
chemical_list: D002135:Calcium-Binding Proteins; D009573:Nitrites; D020011:Protective Agents; D000099211:Phospholamban