Rabbit, a relevant model for the study of cardiac beta 3-adrenoceptors.
Exp Physiol
; 94(4): 400-11, 2009 Apr.
Article
em En
| MEDLINE
| ID: mdl-19151075
ABSTRACT
The beta(3)-adrenoceptors (beta(3)-ARs) have been identified and characterized in the human heart. Specific beta(3)-AR stimulation, unlike beta(1)-AR or beta(2)-AR stimulation, decreases cardiac contractility, partly via the G(i)-NO pathway. However, the precise role of cardiac beta(3)-ARs is not yet completely understood. Indeed, under normal conditions, the beta(3)-AR response is present only to a very low degree in rats and mice. Therefore, we evaluated whether beta(3)-ARs were present and functional in rabbit ventricular cardiomyocytes, and whether the rabbit could serve as a relevant model for the study of cardiac beta(3)-ARs. We used RT-PCR and Western blot to measure the beta(3)-AR transcripts and protein levels in rabbit ventricular cardiomyocytes. We also analysed the effect of beta(3)-AR stimulation using isoproterenol in combination with nadolol or SR 58611A on cardiomyocyte shortening, Ca(2+) transient, L-type Ca(2+) current (I(Ca,L)), delayed rectifier potassium current (I(Ks)) and action potential duration (APD). For the first time, we show that beta(3)-ARs are expressed in rabbit ventricular cardiomyocytes. The mRNA and protein sequences present a high homology to those of rat and human beta(3)-ARs. Furthermore, beta(3)-AR stimulation decreases cardiomyocyte shortening, Ca(2+) transient and I(Ca,L) amplitudes, via a G(i)-NO pathway. Importantly, beta(3)-AR stimulation enhances I(Ks) amplitude and shortens the APD. Taken together, our results indicate that the rabbit provides a relevant model, easily used in laboratories, to study the roles of cardiac beta(3)-ARs in physiological conditions.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sinalização do Cálcio
/
Receptores Adrenérgicos beta 3
/
Miócitos Cardíacos
/
Contração Miocárdica
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
/
Male
Idioma:
En
Revista:
Exp Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2009
Tipo de documento:
Article