Genistein increases the sensitivity of cardiac ion channels to β- adrenergic receptor stimulation

Livia C. Hool, Lisa M. Middleton, Robert D. Harvey

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

The whole-cell patch-clamp technique was used to monitor the effects of genistein, a tyrosine kinase inhibitor, on membrane currents recorded from isolated guinea pig ventricular myocytes. Under control conditions, genistein (50 μmol/L) did not activate the latent cAMP-regulated Cl- current (I(Cl)). However, in the presence of a subthreshold concentration (1 nmol/L) of the β-adrenergic agonist isoproterenol (Iso), genistein caused a near-maximal activation of this current. In the absence of genistein, Iso activated I(Cl) with an EC50 of 5 nmol/L. In the presence of genistein, Iso activated I(Cl) with an EC50 of 0.3 nmol/L. This facilitatory effect was not observed in the presence of daidzein (50 μmol/L), an analogue of genistein that only weakly inhibits tyrosine kinase activity. Furthermore, peroxovanadate, a potent inhibitor of phosphotyrosine phosphatase activity, inhibited I(Cl) activated by Iso alone, and it blocked the stimulatory effect of genistein in the presence of Iso. To determine whether the stimulatory effect of genistein was specific for I(Cl), we also studied its action on the cAMP-regulated delayed rectifier K+ current (I(K)) and L-type Ca2+ current (I(Ca-L)) present in these cells. Basal I(K) and I(Ca-L) were partially (≃30% to 40%) inhibited by genistein. However, this inhibitory effect was mimicked by daidzein, suggesting that inhibition of tyrosine kinase activity is not involved. In addition to the nonspecific inhibitory effect, genistein also caused a significant increase in the β-adrenergic sensitivity of the unblocked cationic currents. In the absence of genistein, 1 nmol/L Iso had no effect on either I(K) or I(Ca-L). However, in the presence of genistein, 1 nmol/L Iso significantly increased the magnitude of both currents. These results suggest that tyrosine kinase activity may play an important role in regulating β-adrenergic responsiveness of the heart.

Original languageEnglish (US)
Pages (from-to)33-42
Number of pages10
JournalCirculation research
Volume83
Issue number1
DOIs
StatePublished - Jul 13 1998

Fingerprint

Genistein
Ion Channels
Adrenergic Receptors
Isoproterenol
Protein-Tyrosine Kinases
Adrenergic Agents
Adrenergic Agonists
Protein Tyrosine Phosphatases
Patch-Clamp Techniques
Muscle Cells
Guinea Pigs

Keywords

  • Cardiac cystic fibrosis transmembrane conductance regulator Cl current
  • Delayed rectifier K current
  • L-type Ca current
  • Phosphotyrosine phosphatase
  • Tyrosine kinase

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Genistein increases the sensitivity of cardiac ion channels to β- adrenergic receptor stimulation. / Hool, Livia C.; Middleton, Lisa M.; Harvey, Robert D.

In: Circulation research, Vol. 83, No. 1, 13.07.1998, p. 33-42.

Research output: Contribution to journalArticle

@article{6d0c1d4ce4fd4f888e1c39209012cb83,
title = "Genistein increases the sensitivity of cardiac ion channels to β- adrenergic receptor stimulation",
abstract = "The whole-cell patch-clamp technique was used to monitor the effects of genistein, a tyrosine kinase inhibitor, on membrane currents recorded from isolated guinea pig ventricular myocytes. Under control conditions, genistein (50 μmol/L) did not activate the latent cAMP-regulated Cl- current (I(Cl)). However, in the presence of a subthreshold concentration (1 nmol/L) of the β-adrenergic agonist isoproterenol (Iso), genistein caused a near-maximal activation of this current. In the absence of genistein, Iso activated I(Cl) with an EC50 of 5 nmol/L. In the presence of genistein, Iso activated I(Cl) with an EC50 of 0.3 nmol/L. This facilitatory effect was not observed in the presence of daidzein (50 μmol/L), an analogue of genistein that only weakly inhibits tyrosine kinase activity. Furthermore, peroxovanadate, a potent inhibitor of phosphotyrosine phosphatase activity, inhibited I(Cl) activated by Iso alone, and it blocked the stimulatory effect of genistein in the presence of Iso. To determine whether the stimulatory effect of genistein was specific for I(Cl), we also studied its action on the cAMP-regulated delayed rectifier K+ current (I(K)) and L-type Ca2+ current (I(Ca-L)) present in these cells. Basal I(K) and I(Ca-L) were partially (≃30{\%} to 40{\%}) inhibited by genistein. However, this inhibitory effect was mimicked by daidzein, suggesting that inhibition of tyrosine kinase activity is not involved. In addition to the nonspecific inhibitory effect, genistein also caused a significant increase in the β-adrenergic sensitivity of the unblocked cationic currents. In the absence of genistein, 1 nmol/L Iso had no effect on either I(K) or I(Ca-L). However, in the presence of genistein, 1 nmol/L Iso significantly increased the magnitude of both currents. These results suggest that tyrosine kinase activity may play an important role in regulating β-adrenergic responsiveness of the heart.",
keywords = "Cardiac cystic fibrosis transmembrane conductance regulator Cl current, Delayed rectifier K current, L-type Ca current, Phosphotyrosine phosphatase, Tyrosine kinase",
author = "Hool, {Livia C.} and Middleton, {Lisa M.} and Harvey, {Robert D.}",
year = "1998",
month = "7",
day = "13",
doi = "10.1161/01.RES.83.1.33",
language = "English (US)",
volume = "83",
pages = "33--42",
journal = "Circulation Research",
issn = "0009-7330",
publisher = "Lippincott Williams and Wilkins",
number = "1",

}

TY - JOUR

T1 - Genistein increases the sensitivity of cardiac ion channels to β- adrenergic receptor stimulation

AU - Hool, Livia C.

AU - Middleton, Lisa M.

AU - Harvey, Robert D.

PY - 1998/7/13

Y1 - 1998/7/13

N2 - The whole-cell patch-clamp technique was used to monitor the effects of genistein, a tyrosine kinase inhibitor, on membrane currents recorded from isolated guinea pig ventricular myocytes. Under control conditions, genistein (50 μmol/L) did not activate the latent cAMP-regulated Cl- current (I(Cl)). However, in the presence of a subthreshold concentration (1 nmol/L) of the β-adrenergic agonist isoproterenol (Iso), genistein caused a near-maximal activation of this current. In the absence of genistein, Iso activated I(Cl) with an EC50 of 5 nmol/L. In the presence of genistein, Iso activated I(Cl) with an EC50 of 0.3 nmol/L. This facilitatory effect was not observed in the presence of daidzein (50 μmol/L), an analogue of genistein that only weakly inhibits tyrosine kinase activity. Furthermore, peroxovanadate, a potent inhibitor of phosphotyrosine phosphatase activity, inhibited I(Cl) activated by Iso alone, and it blocked the stimulatory effect of genistein in the presence of Iso. To determine whether the stimulatory effect of genistein was specific for I(Cl), we also studied its action on the cAMP-regulated delayed rectifier K+ current (I(K)) and L-type Ca2+ current (I(Ca-L)) present in these cells. Basal I(K) and I(Ca-L) were partially (≃30% to 40%) inhibited by genistein. However, this inhibitory effect was mimicked by daidzein, suggesting that inhibition of tyrosine kinase activity is not involved. In addition to the nonspecific inhibitory effect, genistein also caused a significant increase in the β-adrenergic sensitivity of the unblocked cationic currents. In the absence of genistein, 1 nmol/L Iso had no effect on either I(K) or I(Ca-L). However, in the presence of genistein, 1 nmol/L Iso significantly increased the magnitude of both currents. These results suggest that tyrosine kinase activity may play an important role in regulating β-adrenergic responsiveness of the heart.

AB - The whole-cell patch-clamp technique was used to monitor the effects of genistein, a tyrosine kinase inhibitor, on membrane currents recorded from isolated guinea pig ventricular myocytes. Under control conditions, genistein (50 μmol/L) did not activate the latent cAMP-regulated Cl- current (I(Cl)). However, in the presence of a subthreshold concentration (1 nmol/L) of the β-adrenergic agonist isoproterenol (Iso), genistein caused a near-maximal activation of this current. In the absence of genistein, Iso activated I(Cl) with an EC50 of 5 nmol/L. In the presence of genistein, Iso activated I(Cl) with an EC50 of 0.3 nmol/L. This facilitatory effect was not observed in the presence of daidzein (50 μmol/L), an analogue of genistein that only weakly inhibits tyrosine kinase activity. Furthermore, peroxovanadate, a potent inhibitor of phosphotyrosine phosphatase activity, inhibited I(Cl) activated by Iso alone, and it blocked the stimulatory effect of genistein in the presence of Iso. To determine whether the stimulatory effect of genistein was specific for I(Cl), we also studied its action on the cAMP-regulated delayed rectifier K+ current (I(K)) and L-type Ca2+ current (I(Ca-L)) present in these cells. Basal I(K) and I(Ca-L) were partially (≃30% to 40%) inhibited by genistein. However, this inhibitory effect was mimicked by daidzein, suggesting that inhibition of tyrosine kinase activity is not involved. In addition to the nonspecific inhibitory effect, genistein also caused a significant increase in the β-adrenergic sensitivity of the unblocked cationic currents. In the absence of genistein, 1 nmol/L Iso had no effect on either I(K) or I(Ca-L). However, in the presence of genistein, 1 nmol/L Iso significantly increased the magnitude of both currents. These results suggest that tyrosine kinase activity may play an important role in regulating β-adrenergic responsiveness of the heart.

KW - Cardiac cystic fibrosis transmembrane conductance regulator Cl current

KW - Delayed rectifier K current

KW - L-type Ca current

KW - Phosphotyrosine phosphatase

KW - Tyrosine kinase

UR - http://www.scopus.com/inward/record.url?scp=0032514157&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032514157&partnerID=8YFLogxK

U2 - 10.1161/01.RES.83.1.33

DO - 10.1161/01.RES.83.1.33

M3 - Article

C2 - 9670916

AN - SCOPUS:0032514157

VL - 83

SP - 33

EP - 42

JO - Circulation Research

JF - Circulation Research

SN - 0009-7330

IS - 1

ER -