Effects of ryanodine on calcium sequestration in the rat liver.
Biochem Pharmacol
; 42(9): 1799-803, 1991 Oct 09.
Article
em En
| MEDLINE
| ID: mdl-1656999
ABSTRACT
Ryanodine, a highly toxic alkaloid known to react specifically with the Ca2+ release channels in sarcoplasmic reticulum (SR), was employed to study Ca2+ sequestration in the liver. Ryanodine at a 200 microM concentration increased cytosolic free Ca2+ levels and phosphorylase a activity in isolated hepatocytes. These effects may involve microsomal Ca2+ sequestration, because ryanodine, in the presence of inhibitors of mitochondrial Ca2+ uptake, at concentrations of 1 nM, 1 microM, 50 microM and 100 microM decreased 45Ca2+ retention in permeabilized hepatocytes. This inhibition of Ca2+ retention by ryanodine was not due to inhibition of the microsomal Ca(2+)-ATPase. Dantrolene, a compound shown previously to inhibit ryanodine binding in the liver, also decreased 45Ca2+ retention in permeabilized hepatocytes, and activated phosphorylase a. These results show that ryanodine administration alters calcium sequestration in liver. The possibility of the existence of a ryanodine-sensitive Ca(2+)-release channel in liver is discussed.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Rianodina
/
Microssomos Hepáticos
/
Mitocôndrias Hepáticas
/
Canais de Cálcio
Limite:
Animals
Idioma:
En
Revista:
Biochem Pharmacol
Ano de publicação:
1991
Tipo de documento:
Article