beta-Adrenergic and muscarinic receptor expression are regulated in opposite ways during senescence in rat left ventricle.
J Mol Cell Cardiol
; 29(1): 309-19, 1997 Jan.
Article
en En
| MEDLINE
| ID: mdl-9040046
ABSTRACT
The well-known attenuated sensitivity of senescent heart to isoproterenol is accompanied by a decreased beta1-adrenergic receptors (beta1-AR) density, a down regulation process which may involve several molecular modifications and whose understanding is incomplete. Data concerning the M2-R muscarinic receptors (M2-R) are more contradictory. Both the absolute and relative concentrations of beta1-AR and M2-R as well as the coupling protein G alpha s and G alpha(i2) mRNAs were determined by slot-blot analysis in the left ventricles (LVs) of 6-7 week and 22-month-old male Wistar rats. In addition, the beta-AR and M2-R densities were quantitated by radioactive ligand binding. (1) The M2-R mRNA concentration increases by 92+/-32% in senescent as compared to adult animals; by contrast, the density in M2-R remains unchanged, suggesting that the M2-R expression was not exclusively regulated at a pre-translational level. (2) The beta1-AR mRNA concentration was nearly halved (reduced by 46+/-9.5%) and paralleled the 51+/-5.6% diminution of the beta-AR density which resulted exclusively from the decrease of beta1-AR density without change in the beta2-AR concentration, suggesting a pre-translational regulation of the beta1-AR expression. (3) G alpha(i2) mRNA concentration was unchanged, while G alpha s mRNA concentration was reduced by 26+/-4.6% in senescent compared with adult LVs. To conclude, the different components of the adrenergic and muscarinic systems are differentially regulated during aging.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Envejecimiento
/
Receptores Muscarínicos
/
Receptores Adrenérgicos beta 1
/
Subunidades alfa de la Proteína de Unión al GTP Gi-Go
/
Ventrículos Cardíacos
Límite:
Animals
Idioma:
En
Revista:
J Mol Cell Cardiol
Año:
1997
Tipo del documento:
Article
País de afiliación:
Francia