title: [The effects of DR2 on myocardial ischemic postconditioning and its underlying mechanisms].
abstract: OBJECTIVE
  To study the effects of dopamin receptors-2 (DR2) on myocardial ischemic postconditioning and explore its underlying mechanisms.
  
  
  METHODS
  The myocardial ischemic postconditioning (PC) model was established in cultured primary rat neonatal cardiomyocytes which were then randomly assigned in the following groups: Nomial control group, Isehemia/reperfusion (L'R) group, PC (ischemic postconditioning) group, PC + Bro (Bromocriptine, a DB2 antagonist) group, PC + Hal (Haloperidol, a DB2 repressor) and PC + Hal + Bro groups. The lactate dehydrogenase (LDH) and superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in cell medium were analyzed by colorunetry. The cell ultrastructure changes were observed by transmission electron microscope. The cell apoptosis was analyzed using flowcytometiy. The protein expression level of D112 and activity of p-p38 and p-JNK were detected by Western blot.
  
  
  RESULTS
  Compared with the nonnal control group, hR increased the protein expression level of DB2, enhanced LDH activity and MDA content, promoted cell injury and apoptosis, decreased SOD activity, up-regulated the activity of p-p38 and p-JNK. Compared with the hR group, although PC further increased the expression of DR2 protein, it decreased LDH activity and MDA content, cell injury and apoptosis, increased SOD activity, down-regulated activity of p-p38 and p-JNK. Bromocriptine treatment further enhanced PC-induced canlioprotective effect, yet Hal addition attenuated this enhancing effect exerted by bromocriptine.
  
  
  CONCLUSIONS
  The activation of DB2 is involved in the protective effect of ischemic postconditioning on myocardial ischemia/reperfusion injury through down-regulating the activity of p-p38 and p-JNK.
authors.forename: Hong-Zhu
authors.initials: HZ
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Gao
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Hao
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Zhang
authors.forename: Jun-Ting
authors.initials: JT
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D057775:Ischemic Postconditioning; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D032383:Myocytes, Cardiac / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D017448:Receptors, Dopamine D2; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases