Alpha 1- and beta-adrenergic regulation of intracellular Ca2+ levels in brown adipocytes.
Biochem Biophys Res Commun
; 163(1): 292-300, 1989 Aug 30.
Article
em En
| MEDLINE
| ID: mdl-2570572
ABSTRACT
In order to monitor changes in cytosolic Ca2+ levels, brown-fat cells were incubated with the fluorescent Ca2+-indicator fura-2 and the fluorescence intensity ratio followed. The addition of norepinephrine led to a rapid and persistent increase in the cytosolic Ca2+ level, which was dose-dependent with a maximal effect at about 1 microM. The response was diminished in the absence of extracellular Ca2+ and was inhibited more efficiently by phentolamine and prazosin than by propranolol or yohimbine, indicating alpha 1-adrenergic mediation. Accordingly, selective alpha 1-adrenergic stimulation also increased the cytosolic Ca2+ level. However, selective beta-adrenergic stimulation, as well as the adenylate cyclase activator forskolin, were also able to increase the cytosolic Ca2+ level in these cells to a certain extent. It was concluded that the major part of the increase in cytosolic Ca2+ was mediated, as in other cell types, via alpha 1-adrenergic receptors, but that Ca2+ levels were also positively modulated by a cAMP-mediated process. These observations are discussed in relation to known alpha 1/beta synergisms in brown adipose tissue.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tecido Adiposo Marrom
/
Cálcio
/
Receptores Adrenérgicos alfa
/
Receptores Adrenérgicos beta
Limite:
Animals
Idioma:
En
Revista:
Biochem Biophys Res Commun
Ano de publicação:
1989
Tipo de documento:
Article
País de afiliação:
Suécia
País de publicação:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA