Increased beta2-adrenoceptors in doxorubicin-induced cardiomyopathy in rat.
PLoS One
; 8(5): e64711, 2013.
Article
em En
| MEDLINE
| ID: mdl-23741376
ABSTRACT
BACKGROUND:
The toxicity of doxorubicin, leading to an irreversible heart failure, limits its use as chemotherapeutic agent. The beneficial effects of early administration of ß-blocker were reported in patients with heart failure due to doxorubicin, suggesting an important role of ß-adrenoceptors (ß-ARs). This study aimed to identify a putative target (ß-AR and/or its effectors) at the early phase of a chronic doxorubicin-induced cardiomyopathy (Dox-CM) in a rat model.METHODOLOGY:
Dox-CM was induced by six doxorubicin injections (cumulative dose 15 mg x kg(-1)) and validated by echocardiography and left ventricle (LV) catheterization. The ß-AR protein expressions in LV were evaluated by western-blot at days 35 (d35) and 70 (d70) after the first doxorubicin injection. Ex vivo cardiac contractility (dP/dtmax, dP/dtmin) was evaluated on isolated heart in response to specific ß-AR stimulations at d35.RESULTS:
At d35, Dox-CM hearts were characterized by mild LV systolic and diastolic dysfunctions, which were exacerbated at d70. In Dox-CM hearts, ß3-AR expression was only decreased at d70 (-37±8%). At d35, ß1-AR expression was decreased by 68±6%, but ex vivo ß1-AR function was preserved due to, at least in part, an increased adenylyl cyclase response assessed by forskolin. ß2-AR expression was increased both at d35 (+58±22%) and d70 (+174±35%), with an increase of ex vivo ß2-AR response at d35. Inhibition of Gi protein with pertussis toxin did not affect ß2-AR response in Dox-CM hearts, suggesting a decoupling of ß2-AR to Gi protein.CONCLUSION:
This study highlights the ß1/ß2-AR imbalance in early Dox-CM and reveals the important role that ß2-AR/Gi coupling could play in this pathology. Our results suggest that ß2-AR could be an interesting target at early stage of Dox-CM.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Receptores Adrenérgicos beta 2
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Receptores Adrenérgicos beta 1
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Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP
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Coração
/
Cardiomiopatias
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article