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COMPARISON OF LOW and HIGH DOSES OF CARVEDILOL ON RESTORATION OF CARDIAC FUNCTION and CALCIUM‐HANDLING PROTEINS IN RAT FAILING HEART
Author(s) -
Sun YiLan,
Hu ShenJiang,
Wang LiHong,
Hu Ying,
Zhou JianYing
Publication year - 2005
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.2005.04230.x
Subject(s) - carvedilol , serca , phospholamban , medicine , heart failure , cardiac function curve , endocrinology , contractility , downregulation and upregulation , myocardial infarction , cardiology , pharmacology , chemistry , atpase , enzyme , biochemistry , gene
SUMMARY 1. The β‐adrenoceptor antagonist carvedilol reverses cardiac dysfunction in the failing heart. A recent study showed that β‐adrenoceptor antagonists indirectly normalize Ca 2+ ‐regulatory proteins. The relationship between these two phenomena and the suitable dosage of carvedilol remains unclear. 2. We investigated the change in left ventricular (LV) remodelling and function in a rat model of heart failure due to myocardial infarction (MI) with or without carvedilol (30 or 2 mg/kg per day) treatment for 6 weeks. The expression of mRNA and proteins of sarcoplasmic reticulum Ca 2+ ‐ATPase (SERCA) and phospholamban (PLB) in cardiomyocytes was also measured. 3. There was significant LV remodelling and cardiac contractile dysfunction in MI rats. The expression of SERCA mRNA and protein were downregulated ( P < 0.01), but the expression of PLB mRNA and protein were upregulated ( P < 0.01) in MI rats compared with sham‐operated rats. After treatment with carvedilol, LV remodelling and cardiac contractile dysfunction were clearly improved. Low‐dose carvedilol was better at improving some parameters of LV remodelling and function than the high dose. Carvedilol partially restored the low expression of SERCA ( P < 0.05), but had no effect on PLB expression ( P > 0.05). Moreover, low‐dose carvedilol induced a more significant improvement in SERCA expression than did the high dose ( P < 0.05). 4. The results of the present study suggest that carvedilol is effective in improving LV remodelling and cardiac contractile dysfunction after MI. This may be related to the normalization of SERCA expression.