title: Changes in levels of angiotensin II and its receptors in a model of inverted stress-induced cardiomyopathy.
abstract: BACKGROUND
  Stress-induced cardiomyopathy (SIC) has gained increasing attention worldwide and is characterized by extensive ventricular akinesis, Beta-blockers and angiotensin-converting enzyme inhibitors (ACEIs) are the main treatments for SIC patients. The pharmacological mechanism of action of beta-blockers results in the inhibition of the biological effects of catecholamines. However, the mechanism of action of ACEIs in the treatment of cardiomyopathy is not known. Our aim is to assess changes in levels of angiotensin II, angiotensin-II receptors and ACE responses to SIC.
  
  
  METHODS
  A model of inverted SIC was established in rabbits by vagal electrical stimulation. The serum concentration of angiotensin II and angiotensin (1-7) was detected by enzyme-linked immunosorbent assay. Expression of angiotensin-II receptors was measured by Western blotting and real-time reverse transcription-polymerase chain reaction (RT-PCR), with localization detected by immunofluorescent staining. ACE-II expression in the myocardium was measured by Western blotting.
  
  
  RESULTS
  From one day after vagal stimulation, concentrations of angiotensin II were significantly higher in the experimental group than those in the control group (P <0.05). Stress induced a time-dependent decrease in angiotensin subtype-1 (AT1) expression and a time-dependent increase in AT2 expression only in the apical portion of the myocardium. From three days after vagal stimulation, angiotensin (1-7) levels were significantly lower in the experimental group compared with the control group (P <0.05). Expression of the ACE-II protein was significantly downregulated in the experimental group compared with the control group from three days after vagal stimulation (P <0.05).
  
  
  CONCLUSIONS
  Expression of angiotensin II, its receptors, ACE-II and angiotensin (1-7) was altered in response to SIC. The renin-angiotensin system could represent a therapeutic target in the prevention of SIC.
authors.affiliation: Department of Cardiology, Kunming General Hospital of Chengdu Military Command, Daguan Road, No212, Yunnan, 650032, China. 289072156@qq.com.
authors.forename: Yin-yan
authors.initials: YY
authors.lastname: Xi
authors.affiliation: Department of Obstetrics and Gynecology, Kunming General Hospital of Chengdu Military Command, Daguan Road, No212, Yunnan, 650032, China. beia761050@126.com.
authors.forename: Bei
authors.initials: B
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Kunming General Hospital of Chengdu Military Command, Daguan Road, No212, Yunnan, 650032, China. doctorlxyang@163.com.
authors.forename: Li-xia
authors.initials: LX
authors.lastname: Yang
authors.affiliation: Department of Cardiology, Kunming General Hospital of Chengdu Military Command, Daguan Road, No212, Yunnan, 650032, China. 263583871@qq.com.
authors.forename: Chen-wei
authors.initials: CW
authors.lastname: Kuang
authors.affiliation: Department of Cardiology, Kunming General Hospital of Chengdu Military Command, Daguan Road, No212, Yunnan, 650032, China. grw771210@163.com.
authors.forename: Rui-wei
authors.initials: RW
authors.lastname: Guo
mesh_terms: D000803:Angiotensin I / Q000378:metabolism; D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D009202:Cardiomyopathies / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D009206:Myocardium / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D011817:Rabbits; D011945:Receptors, Angiotensin / Q000378:metabolism*; D012084:Renin-Angiotensin System / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology*
chemical_list: D010446:Peptide Fragments; D011945:Receptors, Angiotensin; D000804:Angiotensin II; D000803:Angiotensin I; C118790:angiotensin I (1-7)