Two different types of channels are targets for potassium channel openers in Xenopus oocytes

FEBS Letters

Lazdunski, Michel¹  Honoré, Eric¹ 

[1] Institut de Pharmacologie Moléculaire et Cellulaire du CNRS, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France

关键词: Follicular Xenopus oocyte;    Potassium channel opener;    Glibenclamide;    ATP-sensitive potassium channel;    CK;    cromakalim;    KCOs;    K− channel openers;    KATP channels;    ATP-sensitive K+ channels;    HEPES;    N-2-hydroxyethyl-piperazine-N'-2-ethanesulfonic acid;    EGTA;    ethyleneglycol-bis-(β-aminoethylether)N;    N;    N';    N';    -tetraacetic acid;    I-V relationship;    current-voltage relationship;    TEA;    tetraethylammonium;    4AP;    4-aminopyridine;    MCD peptide;    mast cell degranulating peptide;    RP49356;    N-methyl;    2-[-3-pyridil]-tetrahydrothiopyran-2-carbothiamide-1-oxide;    BRL34915;    6-cyano-3;    4-dihydro-2;    2-dimethyl-trans-4-[2-oxo-l-pyrrolidyl]-2H-benzo[b]-pyran-3-ol;    P1060;    N-tert-butyl-N'-cyano-N' '-3-pyridinylguanidine;    P1075;    N-tert-pentyl-N'-cyano-N-3-pyridinylguanidine;   

DOI  :  10.1016/0014-5793(91)80019-Y

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

K⁺ channel openers elicit K⁺ currents in follicle-enclosed Xenopus oocytes. The most potent activators are the pinacidil derivatives P1075 and P1060. The rank order of potency to activate K ⁺ currents in follicle-enclosed oocytes was: P1075 (K_0.5: 5 μM)>P1060 (K_0.5: 12 μM)> BRL38227 (lemakalim) (K_0.5:77 μM)>RP61419 (K_0.5:100 μM)>(−)pinacidil (K_0.5:300 μM). Minoxidil sulfate, nicorandil. RP49356 and diazoxide were ineffective. Activation by the K⁺ channel openers could be abolished by the antidiabetic sulfonylurea glibenclamide. It was not affected by the blocker of the Ca²⁺-activated K⁺ channels charybdotoxin. The various K⁺ channel openers failed to activate glibenclamide-sensitive K⁺ channels in defolliculated oocytes, but BRL derivatives (K_0.5 for BRL38226 is 150 μM) and RP61419 inhibited a background current. The channel responsible for this background current is K⁺ permeable but not fully selective for K⁺. It is resistant to glibenclamide. It is inhibited by Ba²⁺, 4-aminopyridine. Co²⁺,.Ni²⁺ and La³⁺.

【 授权许可】

Unknown