Genistein inhibition of fast Na+ current in uterine leiomyosarcoma cells is independent of tyrosine kinase inhibition

Biochim Biophys Acta. 1996 Jan 12;1278(1):1-4. doi: 10.1016/0005-2736(95)00238-3.


Possible regulation of fast Na+ channels by tyrosine kinase was examined in human uterine smooth muscle cell line, using whole-cell voltage clamp (at a holding potential of - 90 mV). Bath application of genistein, an inhibitor tyrosine kinase, decreased the fast Na+ current (INa(f)) dose-dependently. The maximal inhibition of INa(f) was 98%, and the concentration for half-maximal inhibition (IC50) was 9 microM. The effect of genistein was rapidly reversible. Daidzein, an inactive analog of genistein, had a similar inhibitory effect on INa(f). These results suggest that the fast Na+ channels in uterine sarcoma cells may be directly blocked by genistein and daidzein, i.e., their effect may be independent of tyrosine kinase inhibition.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Electrochemistry
  • Enzyme Inhibitors / pharmacology
  • Estrogens, Non-Steroidal / pharmacology
  • Female
  • Genistein
  • Humans
  • Isoflavones / pharmacology*
  • Leiomyosarcoma
  • Myometrium / drug effects
  • Myometrium / metabolism*
  • Patch-Clamp Techniques
  • Protein-Tyrosine Kinases / antagonists & inhibitors*
  • Protein-Tyrosine Kinases / metabolism
  • Sodium Channel Blockers*
  • Tumor Cells, Cultured


  • Enzyme Inhibitors
  • Estrogens, Non-Steroidal
  • Isoflavones
  • Sodium Channel Blockers
  • daidzein
  • Genistein
  • Protein-Tyrosine Kinases