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Document Details : Title: Angiotensin-converting enzyme inhibitor improves force and Ca2+-frequency relationship in myocytes from rats with hart failure Author(s): LIAO, X. , HE, J. , MA, H. , TAO, J. , CHEN, W. , LENG, X. , MAI, W. , ZHEN, W. , LIU, J. , WANG, L. Journal: Acta Cardiologica Volume: 62 Issue: 2 Date: 2007 Pages: 157-162 DOI: 10.2143/AC.62.2.2020236 Abstract : Objectives — The objectives were to study the effects of an ACE inhibitor on the force-frequency relationship (FFR) and its possible mechanism in isolated failing myocytes. Methods and results — Male Wistar rats were randomized into a heart failure group treated with perindopril (CHF-T, 3 mg.kg-1.d-1), a heart failure group without treatment (CHF-C) and a sham-operated group (PS). Heart failure was induced by constriction of the abdominal aorta. All groups were further followed up for 12 weeks. Left ventricular myocytes were isolated. Cell-shortening fraction (FS) and intracellular calcium transients were measured at different frequency field stimulations. A negative force-frequency relationship (FFR) was found in the CHF-C group compared with the positive-negative biphasic FFR in the PS group, and a flat FFR in the CHF-T group. Intracellular Ca2+ frequency relationships (CaFRs) were positive-negative biphasic in both the PS and CHF-T groups, whereas a negative CaFR was found in the CHF-C group. Regardless of the stimulation frequency, FS significantly correlated with [Ca2+]imax in the PS or CHF-C groups. Compared to the PS group, protein levels of SERCA2 significantly decreased and NCX1 increased in the CHF-C group. In the CHF-T group, these changes were reduced. Conclusion — The ACE inhibitor could improve the impaired FFR of isolated failing myocytes. This effect was possibly mediated via ameliorating the disturbance of CaFR. |
