title: [Delayed protective effect of morphine preconditioning on rabbit myocardium].
abstract: OBJECTIVE
  To investigate whether morphine preconditioning has the delayed protective effect on rabbit myocardium.
  
  
  METHODS
  Thirty New Zealand white rabbits were randomly divided into a NS group, a Mor-12 group and a Mor-24 group (n=10). In the Mor-12 group and Mor-24 group, morphine (3 mg/kg) was infused into rabbits, while the same volume of normal saline (NS) was given to rabbits in the NS group. Twelve hours after morphine infusion in the Mor-12 group, 24 h after NS or morphine infusion in the NS group and Mor-24 group, rabbits were subjected to 30 min left anterior descending coronary artery occlusions and were reperfused for 120 min. In 8 of the 10 rabbits in each group, arterial blood samples were taken before the ischemia (T1), 30 min after the ischemia (T2) and 120 min after the reperfusion (T3) to determine the concentration of cardiac troponin I (cTnI), and the myocardial infarct area was determined at the end of reperfusion. In the other 2 of the 10 rabbits in each group,the cell ultramicro-structure injury of myocardium was examined by electron microscope at the end of reperfusion.
  
  
  RESULTS
  The concentration of cTnI at T2 and T3 in the Mor-24 group was lower than that in the NS group and Mor-12 group.The myocardial infarct size, and cell ultramicrostructure injury of myocardium in the Mor-24 group were decreased compared with the NS group and Mor-12 group.
  
  
  CONCLUSIONS
  Morphine preconditioning has delayed protective effect on rabbit myocardium.
authors.affiliation: Department of Geriatrics , Second Xiangya Hospital, Central South University, Changsha 410011, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Long
authors.forename: Dingquan
authors.initials: D
authors.lastname: Zou
authors.forename: Rong
authors.initials: R
authors.lastname: Tan
mesh_terms: D000818:Animals; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D009020:Morphine / Q000494:pharmacology*; D015428:Myocardial Reperfusion Injury / Q000473:pathology / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure; D011817:Rabbits; D011897:Random Allocation; D013997:Time Factors; D019210:Troponin I / Q000097:blood*
chemical_list: D019210:Troponin I; D009020:Morphine