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[Effects of metoprolol on cardiac function and myocyte calcium regulatory protein expressions in rabbits with experimental heart failure].
- Source :
-
Zhonghua xin xue guan bing za zhi [Zhonghua Xin Xue Guan Bing Za Zhi] 2007 May; Vol. 35 (5), pp. 476-9. - Publication Year :
- 2007
-
Abstract
- Objective: To investigate the effects of metoprolol on cardiac function and myocyte calcium regulatory protein expressions in rabbits with heart failure.<br />Methods: Rabbit heart failure model was established by aortic insufficiency induced volume overload followed 14 days later by pressure overload induced by abdominal aorta constricting (HF, n = 11), another 8 rabbits with heart failure were treated with metoprolol (ME) for 6 weeks, sham-operated rabbits (n = 11) served as control. Cardiac function was measured by echocardiography at the end of study. Caffeine-induced calcium transients of myocytes loaded by Fluo-3/AM were observed under Laser scanning confocal microscope. Calcium regulatory protein expression was determined by Western blot analysis.<br />Results: Compared to control animals, the ejection fractions [EF, (45.7 +/- 3.0)% vs. (72. 6 +/- 5.0)%, P < 0.01] and the amplitude of caffeine-induced calcium transients [(16.0 +/- 3.5) FI vs. (43.5 +/- 6.2) FI, P < 0.01] were significantly decreased while its time to peak was significantly prolonged [(129.8 +/- 14.5) s vs. (52.2 +/- 7.4) s, P < 0.01] in HF rabbits. The RyR2 (0.106 +/- 0.007 vs. 0.203 +/- 0.021, P < 0.01) and the ratio of SERCA2a and NCX (1.22 +/- 0.23 vs. 1.96 +/- 0.12, P < 0.01) were also significantly reduced in myocytes of HF rabbits. Metoprolol significantly attenuated the decrease of EF [(60.2 +/- 5.1)%], the amplitude of calcium transient [(32.8 +/- 5.4) FI], the RyR2 expression (0.164 +/- 0.016) and the ratio of SERCA2a and NCX (1.68 +/- 0.17, all P < 0.05 vs. HF rabbits) and attenuated the increase of the time to peak of caffeine-induced calcium transients [(91.4 +/- 10.9) s, P < 0.05 vs. HF rabbits].<br />Conclusion: Metoprolol could improve the cardiac function possibly by preventing the alterations of calcium regulatory proteins and increasing calcium transients in failing heart.
- Subjects :
- Animals
Aortic Valve Insufficiency drug therapy
Calcium metabolism
Calcium-Binding Proteins metabolism
Disease Models, Animal
Heart Failure drug therapy
Metoprolol therapeutic use
Rabbits
Aortic Valve Insufficiency metabolism
Heart Failure metabolism
Metoprolol pharmacology
Myocytes, Cardiac drug effects
Myocytes, Cardiac metabolism
Subjects
Details
- Language :
- Chinese
- ISSN :
- 0253-3758
- Volume :
- 35
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Zhonghua xin xue guan bing za zhi
- Publication Type :
- Academic Journal
- Accession number :
- 17711695