Magnesium gating of cardiac gap junction channels.

• 松岡, 達

• Kurata, Yasutaka

• Oka, Chiaki

• Matsuoka, Satoshi

• Noma, Akinori

抄録

We aimed to study kinetics of modulation by intracellular Mg(2+) of cardiac gap junction (Mg(2+) gate). Paired myocytes of guinea-pig ventricle were superfused with solutions containing various concentrations of Mg(2+). In order to rapidly apply Mg(2+) to one aspect of the gap junction, the non-junctional membrane of one of the pair was perforated at nearly the connecting site by pulses of nitrogen laser beam. The gap junction conductance (G(j)) was measured by clamping the membrane potential of the other cell using two-electrode voltage clamp method. The laser perforation immediately increased G(j), followed by slow G(j) change with time constant of 3.5 s at 10 mM Mg(2+). Mg(2+) more than 1.0 mM attenuated dose-dependently the gap junction conductance and lower Mg(2+) (0.6 mM) increased G(j) with a Hill coefficient of 3.4 and a half-maximum effective concentration of 0.6 mM. The time course of G(j) changes was fitted by single exponential function, and the relationship between the reciprocal of time constant and Mg(2+) concentration was almost linear. Based on the experimental data, a mathematical model of Mg(2+) gate with one open state and three closed states well reproduced experimental results. One-dimensional cable model of thirty ventricular myocytes connected to the Mg(2+) gate model suggested a pivotal role of the Mg(2+) gate of gap junction under pathological conditions.

収録刊行物

• Progress in biophysics and molecular biology

  Progress in biophysics and molecular biology 103 (1), 102-110, 2010-09

  Elsevier Ltd

キーワード

• Gap junction channel
• Chemical gating
• Numerical ventricular cell model
• Arrhythmia
• Mg2+

詳細情報

• CRID: 1050282677154726912
• NII論文ID: 120002511391
• NII書誌ID: AA00789136
• ISSN: 00796107
• HANDLE: 2433/128921
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • CiNii Articles