Ca^<2+>-Dependent Inhibition of Inwardly Rectifying K^+ Channel in Opossum Kidney Cells

この論文にアクセスする

この論文をさがす

著者

抄録

The effect of intracellular Ca<sup>2+</sup> on the activity of the inwardly rectifying ATP-regulated K<sup>+</sup> channel with an inward conductance of about 90 pS was examined by using the patch-clamp technique in opossum kidney proximal tubule (OKP) cells. The activity of the inwardly rectifying K<sup>+</sup> channel rapidly declined with an application of ionomycin (1 μM) in the presence of 10<sup>−6</sup> M Ca<sup>2+</sup> in cell-attached patches. The application of 10 μM phorbor-12-myristate-acetate (PMA) with 10<sup>−6</sup> M Ca<sup>2+</sup> reduced the K<sup>+</sup> channel activity. Although the channel activity was not influenced by an increase of bath Ca<sup>2+</sup> from 10<sup>−7.5</sup> to 10<sup>−6</sup> M, the activity was inhibited by protein kinase C (PKC, 1 U/ml) with 10<sup>−6</sup> M Ca<sup>2+</sup> in inside-out patches. The inhibitory effect of Ca<sup>2+</sup> with ionomycin on the channel activity was diminished by the pretreatment with a specific PKC inhibitor, GF 109203X (5 μM), in cell-attached patches. By contrast, the application of Ca<sup>2+</sup>/calmodulin kinase II (CaMK II, 300 pM) dramatically increased this channel activity in inside-out patches. In cell-attached patches, the addition of both GF 109203X and cyclospolin A (5 μM), a potent inhibitor of protein phosphatase 2B (calcineurin), instead stimulated the K<sup>+</sup> channel activity with ionomycin and 10<sup>−6</sup> M Ca<sup>2+</sup>. The addition of protein phosphatase 2B (calcineurin) (2 U/ml) to the bath with calmodulin (1 μM) and Ni<sup>2+</sup> (10 μM) to stimulate calcineurin inhibited the channel activity in inside-out patches. Furthermore, the inhibitory effect of PKC or calcineurin on this channel activity was abolished by a removal of Ca<sup>2+</sup> from bath solution. These results suggest that Ca<sup>2+</sup>-dependent inhibitory effect on the inwardly rectifying K<sup>+</sup> channel in OKP cells was mainly mediated by Ca<sup>2+</sup>-PKC-mediated phosphorylation, and that the Ca<sup>2+</sup>-calmodulin-dependent phosphorylation process may be counterbalanced by the Ca<sup>2+</sup>-calmodulin-dependent dephosphorylation process.<br>

収録刊行物

  • The Japanese journal of physiology

    The Japanese journal of physiology 51(3), 371-380, 2001-06

    PHYSIOLOGICAL SOCIETY OF JAPAN

参考文献:  42件中 1-42件 を表示

被引用文献:  2件中 1-2件 を表示

各種コード

  • NII論文ID(NAID)
    10008293906
  • NII書誌ID(NCID)
    AA00691224
  • 本文言語コード
    ENG
  • 資料種別
    ART
  • ISSN
    0021521X
  • NDL 記事登録ID
    5840332
  • NDL 雑誌分類
    ZS8(科学技術--医学--解剖学・生理学・生化学)
  • NDL 請求記号
    Z53-D40
  • データ提供元
    CJP書誌  CJP引用  NDL  J-STAGE 
ページトップへ