SULFHYDRYL OXIDATION INDUCES RAPID AND REVERSIBLE CLOSURE OF THE ATP-REGULATED K+ CHANNEL IN THE PANCREATIC BETA-CELL

被引：80

作者：

ISLAM, MS ^{[1
]}

BERGGREN, PO ^{[1
]}

LARSSON, O ^{[1
]}

机构：

[1] KAROLINSKA INST, KAROLINSKA HOSP, DEPT ENDOCRINOL, ROLF LUFT CTR DIABET RES, S-10401 STOCKHOLM 60, SWEDEN

来源：

FEBS LETTERS | 1993年 / 319卷 / 1-2期

关键词：

ATP-REGULATED K+ CHANNEL; SULFHYDRYL REAGENT; THIMEROSAL; PANCREATIC BETA-CELL;

D O I：

10.1016/0014-5793(93)80051-U

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Effects of sulfhydryl modification on the ATP regulated K+ channel (K(ATP) channel) in the pancreatic beta-cell were studied, using the patch clamp technique. Application of the sulfhydryl oxidizing agents thimerosal and 2,2-dithio-bis(5-nitropyridine) (DTBNP), in micromolar concentrations, caused complete inhibition of the K(ATP) channel, in inside-out patches. The inhibition was rapid and was rapid and was reversed by the disulfide reducing agents dithiothreitol and cysteine. Thimerosal, which is poorly membrane permeable, inhibited channel activity, only when applied. to the intracellular face of the plasma membrane. In contrast, DTBNP, which is highly lipophilic, caused closure of the K(ATP) channel and consequent depolarization of the membrane potential, also when applied extracellularly. Our results indicate the presence of accessible free SH groups on the cytoplasmic side of the K(ATP) channel in the pancreatic beta-cell. These SH groups are essential for channel function and it is possible that thiol-dependent redox mechanisms can modulate K(ATP) channel activity.

引用

页码：128 / 132

页数：5

共 41 条

[21] PANCREATIC BETA-CELL RECOGNITION OF INSULIN SECRET SECRETAGOGUES - INHIBITORY EFFECTS OF A MEMBRANE PROBE ON ISLET UPTAKE AND INSULIN-RELEASING ACTION OF GLIBENCLAMIDE .6. [J].