Background Nonselective Cationic Current and the Resting Membrane Potential in Rabbit Aorta Endothelial Cells

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Author(s)

Abstract

The ion channel conductances that regulate the membrane potential was investigated by using a perforated patch-clamp technique in rabbit aorta endothelial cells (RAECs). The whole-cell current/voltage (I-V) relation showed a slight outward rectification under physiological ionic conditions. The resting membrane potential was −23.3 ± 1.1 mV (mean ± SEM, n = 19). The slope conductances at the potentials of −80 and 50 mV were 31.0 ± 4.0 and 62.8 ± 7.1 pS pF<sup>−1</sup>, respectively (n = 15). Changes in the extracellular and intracellular Cl<sup>−</sup> concentrations did not affect the reversal potential on I-V curves. The background nonselective cationic (NSC) current was isolated after the K<sup>+</sup> current was suppressed. The relative permeabilities calculated from the changes in reversal potentials using the constant-field theory were P<sub>K</sub>:P<sub>Cs</sub>:P<sub>Na</sub>:P<sub>Li</sub> = 1:0.87:0.40:0.27 and P<sub>Cs</sub>:P<sub>Ca</sub> = 1:0.21. Increases in the external Ca<sup>2+</sup> decreased the background NSC current in a dose-dependent manner. The concentration for half block by Ca<sup>2+</sup> was 1.1 ± 0.3 mM (n = 7). Through the continuous recording of the membrane potential in a current-clamp mode, it was found that the background NSC conductance is the major determinant of resting membrane potential. Taken together, it could be concluded that the background NSC channels function as the major determinant for the resting membrane potential and can be responsible for the background Ca<sup>2+</sup> entry pathway in freshly isolated RAECs.<br>

Journal

  • The Japanese Journal of Physiology

    The Japanese Journal of Physiology 50(6), 635-643, 2000-12-01

    THE PHYSIOLOGICAL SOCIETY OF JAPAN

References:  20

Codes

  • NII Article ID (NAID)
    10008292555
  • NII NACSIS-CAT ID (NCID)
    AA00691224
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    0021521X
  • NDL Article ID
    5706399
  • NDL Source Classification
    ZS8(科学技術--医学--解剖学・生理学・生化学)
  • NDL Call No.
    Z53-D40
  • Data Source
    CJP  NDL  J-STAGE 
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