L-type Ca2+ current in guinea pig ventricular myocytes treated with modulators of tyrosine phosphorylation.
Am J Physiol
; 276(5): H1724-33, 1999 05.
Article
em En
| MEDLINE
| ID: mdl-10330259
ABSTRACT
Guinea pig ventricular myocytes in whole cell configuration were treated with tyrosine kinase (TK) inhibitors [genistein (Gst), tyrphostin A23 (T23), and tyrphostin A25 (T25)] and with inactive analogs [daidzein, genistin, and tyrphostin A1 (T1)] to measure effects on L-type Ca2+ current (ICa,L). Gst inhibited ICa,L (IC50 = 47 microM) without affecting its time course or shifting the ICa, L-voltage relationship. At the highest concentration of isoflavone tested (200 microM), ICa,L was inhibited by 66 +/- 7% (Gst), 22 +/- 2% (daidzein), and 1 +/- 3% (genistin). Inhibition of ICa,L by the active tyrphostins was significantly larger than inhibition by T1; at 200 microM the inhibitions were 72 +/- 6% (T23), 71 +/- 6% (T25), and 27 +/- 6% (T1). The phosphotyrosine phosphatase inhibitor orthovanadate (1 mM) had a small stimulatory effect (6 +/- 2%) on basal ICa,L and blocked the inhibition of ICa,L by TK inhibitors. The data suggest a role for the TK-phosphotyrosine phosphatase system in the regulation of cardiac Ca2+ channels.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tirosina
/
Canais de Cálcio
/
Fibras Musculares Esqueléticas
/
Miocárdio
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol
Ano de publicação:
1999
Tipo de documento:
Article