Effects of calcium buffers and temperature on the β-receptor-mediated regulation of the slowly activating potassium current (I(Ks)) in guinea pig cardiac myocytes

A. E. Busch, James Maylie

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The slowly activating potassium current, termed I(Ks) [1], was measured in guinea pig ventricular myocytes with the whole-cell patch clamp configuration. With low concentrations of Ca2+ buffer (0.1 mM EGTA or BAPTA) in the recording pipette, a temperature increase from 21 to 31 °C dramatically accelerated activation of I(Ks). Isoproterenol increased I(Ks) under such conditions 2- to 3-fold at both temperatures. With high internal Ca buffer concentrations (EGTA or BAPTA ≥ 10 mM), I(Ks) was regulated by isoproterenol at 31 °C but not at 21 °C. We conclude that β-receptor regulation of I(Ks) is temperature and [Ca2+](i) dependent. A mechanism consistent with the results is that Ca2+ and temperature increase the availability of subunits for channel formation and regulation by the β- adrenergic pathway.

Original languageEnglish (US)
Pages (from-to)1-9
Number of pages9
JournalCellular Physiology and Biochemistry
Volume4
Issue number1-2
StatePublished - 1994
Externally publishedYes

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Cardiac Myocytes
Potassium
Buffers
Guinea Pigs
Calcium
Temperature
Egtazic Acid
Isoproterenol
Adrenergic Agents
Muscle Cells
1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid

ASJC Scopus subject areas

  • Cell Biology
  • Physiology

Cite this

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abstract = "The slowly activating potassium current, termed I(Ks) [1], was measured in guinea pig ventricular myocytes with the whole-cell patch clamp configuration. With low concentrations of Ca2+ buffer (0.1 mM EGTA or BAPTA) in the recording pipette, a temperature increase from 21 to 31 °C dramatically accelerated activation of I(Ks). Isoproterenol increased I(Ks) under such conditions 2- to 3-fold at both temperatures. With high internal Ca buffer concentrations (EGTA or BAPTA ≥ 10 mM), I(Ks) was regulated by isoproterenol at 31 °C but not at 21 °C. We conclude that β-receptor regulation of I(Ks) is temperature and [Ca2+](i) dependent. A mechanism consistent with the results is that Ca2+ and temperature increase the availability of subunits for channel formation and regulation by the β- adrenergic pathway.",
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AU - Maylie, James

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N2 - The slowly activating potassium current, termed I(Ks) [1], was measured in guinea pig ventricular myocytes with the whole-cell patch clamp configuration. With low concentrations of Ca2+ buffer (0.1 mM EGTA or BAPTA) in the recording pipette, a temperature increase from 21 to 31 °C dramatically accelerated activation of I(Ks). Isoproterenol increased I(Ks) under such conditions 2- to 3-fold at both temperatures. With high internal Ca buffer concentrations (EGTA or BAPTA ≥ 10 mM), I(Ks) was regulated by isoproterenol at 31 °C but not at 21 °C. We conclude that β-receptor regulation of I(Ks) is temperature and [Ca2+](i) dependent. A mechanism consistent with the results is that Ca2+ and temperature increase the availability of subunits for channel formation and regulation by the β- adrenergic pathway.

AB - The slowly activating potassium current, termed I(Ks) [1], was measured in guinea pig ventricular myocytes with the whole-cell patch clamp configuration. With low concentrations of Ca2+ buffer (0.1 mM EGTA or BAPTA) in the recording pipette, a temperature increase from 21 to 31 °C dramatically accelerated activation of I(Ks). Isoproterenol increased I(Ks) under such conditions 2- to 3-fold at both temperatures. With high internal Ca buffer concentrations (EGTA or BAPTA ≥ 10 mM), I(Ks) was regulated by isoproterenol at 31 °C but not at 21 °C. We conclude that β-receptor regulation of I(Ks) is temperature and [Ca2+](i) dependent. A mechanism consistent with the results is that Ca2+ and temperature increase the availability of subunits for channel formation and regulation by the β- adrenergic pathway.

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