Angiotensin II desensitization and Ca2+ and Na+ fluxes in vascular smooth muscle cells.
Pflugers Arch
; 415(2): 230-4, 1989 Nov.
Article
en En
| MEDLINE
| ID: mdl-2594478
ABSTRACT
The role of ion fluxes in angiotensin II (AII) desensitization (tachyphylaxis) was investigated by studying Na+ and Ca2+ translocation in cultured vascular smooth muscle cells from the rat aorta. The effects of AII were compared to those of [1-sarcosine]-AII (Sar1-AII), an analogue which also induces tachyphylaxis, and [2-lysine]-AII (Lys2-AII), an analogue that does not show this property. Maximally effective concentrations of the three peptides induced a rapid and transient increase in 45Ca2+ efflux, a rapid and sustained decrease in total cell Ca2+ and an increased Na+ permeability. Repeated treatments, at short intervals, with either of the three peptides abolished the effect on Ca2+ efflux, and this desensitization was slowly reversible. A 30-min rest period was sufficient for full recovery of the response of cells that were desensitized by Lys2-AII, whereas the recovery from AII or Sar1-AII-desensitization was still not complete after 60 min. Our results suggest that the difference in the behaviour of the "tachyphylactic" AII and Sar1-AII and the "non-tachyphylactic" Lys2-AII lays not in the production of different signals upon binding to the receptor, but in a difference in the hormone-receptor interaction itself.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Sodio
/
Angiotensina II
/
Calcio
/
Músculo Liso Vascular
Límite:
Animals
Idioma:
En
Revista:
Pflugers Arch
Año:
1989
Tipo del documento:
Article
País de afiliación:
Brasil