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. 1987 Oct;391:611–629. doi: 10.1113/jphysiol.1987.sp016759

The effects of magnesium upon adenosine triphosphate-sensitive potassium channels in a rat insulin-secreting cell line.

I Findlay 1
PMCID: PMC1192235  PMID: 2451014

Abstract

1. The patch-clamp method of single-channel recording was applied to K+ channels which are inhibited by intracellular adenosine 5'-triphosphate (ATP: K+-ATP channels) in membrane patches obtained from the insulin-secreting cloned cell line RINm5F. 2. The magnitude of K+ currents flowing outwards through these K+-ATP channels was reduced by internal Mg2+ ions in a dose-dependent manner. Currents flowing inwards through the channels were not affected by Mg2+. Internal Na+ ions had similar effects. 3. Divalent cations (Mg2+, Sr2+ and Ca2+) applied to the internal surface of the patch membrane inhibited the opening of K+-ATP channels in a dose-dependent manner. Internal Na+ ions had no effect. 4. K+-ATP channel activity was stimulated by adenosine 5'-diphosphate (ADP), guanosine 5'-triphosphate (GTP), guanosine 5'-diphosphate (GDP), guanosine 5'-o-(3-thiotriphosphate) (GTP gamma S) and guanosine 5'-o-(2-thiodiphosphate) (GDP beta S) when millimolar Mg2+ bathed the internal surface of the patch membrane. In the virtual absence of internal Mg2+ ions ADP, GTP, and GTP gamma S inhibited K+-ATP channels and GDP and GDP beta S were without effect. Adenosine 5'-o-(2-thiodiphosphate) (ADP beta S) inhibited K+-ATP channel activity in the presence and absence of Mg2+. 5. K+-ATP channel openings could be evoked by either ADP or GDP in the presence of an inhibitory concentration of ATP. These openings were abolished in the absence of internal Mg2+. 6. Run-down K+-ATP channels could be reactivated by ATP in the presence of internal Mg2+, but not in its absence. Analogues of ATP were unable to reactivate K+-ATP channels even in the presence of Mg2+. 7. It is concluded that internal Mg2+ ions (i) cause the rectification of the K+-ATP channel current-voltage relationship, (ii) are required for K+-ATP channel activity to be maintained by a phosphorylation process and (iii) are required for K+-ATP channel activity evoked by ADP, GTP and GDP.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Ashcroft F. M., Harrison D. E., Ashcroft S. J. Glucose induces closure of single potassium channels in isolated rat pancreatic beta-cells. 1984 Nov 29-Dec 5Nature. 312(5993):446–448. doi: 10.1038/312446a0. [DOI] [PubMed] [Google Scholar]
  2. Bechem M., Glitsch H. G., Pott L. Properties of an inward rectifying K channel in the membrane of guinea-pig atrial cardioballs. Pflugers Arch. 1983 Nov;399(3):186–193. doi: 10.1007/BF00656713. [DOI] [PubMed] [Google Scholar]
  3. Benham C. D., Bolton T. B., Lang R. J., Takewaki T. The mechanism of action of Ba2+ and TEA on single Ca2+-activated K+ -channels in arterial and intestinal smooth muscle cell membranes. Pflugers Arch. 1985 Feb;403(2):120–127. doi: 10.1007/BF00584088. [DOI] [PubMed] [Google Scholar]
  4. Cecchi X., Alvarez O., Wolff D. Characterization of a calcium-activated potassium channel from rabbit intestinal smooth muscle incorporated into planar bilayers. J Membr Biol. 1986;91(1):11–18. doi: 10.1007/BF01870210. [DOI] [PubMed] [Google Scholar]
  5. Cook D. L., Hales C. N. Intracellular ATP directly blocks K+ channels in pancreatic B-cells. Nature. 1984 Sep 20;311(5983):271–273. doi: 10.1038/311271a0. [DOI] [PubMed] [Google Scholar]
  6. Dunne M. J., Findlay I., Petersen O. H., Wollheim C. B. ATP-sensitive K+ channels in an insulin-secreting cell line are inhibited by D-glyceraldehyde and activated by membrane permeabilization. J Membr Biol. 1986;93(3):271–279. doi: 10.1007/BF01871181. [DOI] [PubMed] [Google Scholar]
  7. Dunne M. J., Petersen O. H. GTP and GDP activation of K+ channels that can be inhibited by ATP. Pflugers Arch. 1986 Nov;407(5):564–565. doi: 10.1007/BF00657518. [DOI] [PubMed] [Google Scholar]
  8. Dunne M. J., Petersen O. H. Intracellular ADP activates K+ channels that are inhibited by ATP in an insulin-secreting cell line. FEBS Lett. 1986 Nov 10;208(1):59–62. doi: 10.1016/0014-5793(86)81532-0. [DOI] [PubMed] [Google Scholar]
  9. Fabiato A., Fabiato F. Calculator programs for computing the composition of the solutions containing multiple metals and ligands used for experiments in skinned muscle cells. J Physiol (Paris) 1979;75(5):463–505. [PubMed] [Google Scholar]
  10. Findlay I., Dunne M. J. ATP maintains ATP-inhibited K+ channels in an operational state. Pflugers Arch. 1986 Aug;407(2):238–240. doi: 10.1007/BF00580683. [DOI] [PubMed] [Google Scholar]
  11. Findlay I., Dunne M. J., Petersen O. H. ATP-sensitive inward rectifier and voltage- and calcium-activated K+ channels in cultured pancreatic islet cells. J Membr Biol. 1985;88(2):165–172. doi: 10.1007/BF01868430. [DOI] [PubMed] [Google Scholar]
  12. Findlay I., Dunne M. J., Petersen O. H. High-conductance K+ channel in pancreatic islet cells can be activated and inactivated by internal calcium. J Membr Biol. 1985;83(1-2):169–175. doi: 10.1007/BF01868748. [DOI] [PubMed] [Google Scholar]
  13. Findlay I., Dunne M. J., Ullrich S., Wollheim C. B., Petersen O. H. Quinine inhibits Ca2+-independent K+ channels whereas tetraethylammonium inhibits Ca2+-activated K+ channels in insulin-secreting cells. FEBS Lett. 1985 Jun 3;185(1):4–8. doi: 10.1016/0014-5793(85)80729-8. [DOI] [PubMed] [Google Scholar]
  14. Flatman P. W. Magnesium transport across cell membranes. J Membr Biol. 1984;80(1):1–14. doi: 10.1007/BF01868686. [DOI] [PubMed] [Google Scholar]
  15. Golowasch J., Kirkwood A., Miller C. Allosteric effects of Mg2+ on the gating of Ca2+-activated K+ channels from mammalian skeletal muscle. J Exp Biol. 1986 Sep;124:5–13. doi: 10.1242/jeb.124.1.5. [DOI] [PubMed] [Google Scholar]
  16. Halban P. A., Praz G. A., Wollheim C. B. Abnormal glucose metabolism accompanies failure of glucose to stimulate insulin release from a rat pancreatic cell line (RINm5F). Biochem J. 1983 May 15;212(2):439–443. doi: 10.1042/bj2120439. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
  18. Hunter M., Lopes A. G., Boulpaep E. L., Giebisch G. H. Single channel recordings of calcium-activated potassium channels in the apical membrane of rabbit cortical collecting tubules. Proc Natl Acad Sci U S A. 1984 Jul;81(13):4237–4239. doi: 10.1073/pnas.81.13.4237. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Iwatsuki N., Petersen O. H. Action of tetraethylammonium on calcium-activated potassium channels in pig pancreatic acinar cells studied by patch-clamp single-channel and whole-cell current recording. J Membr Biol. 1985;86(2):139–144. doi: 10.1007/BF01870780. [DOI] [PubMed] [Google Scholar]
  20. Iwatsuki N., Petersen O. H. Inhibition of Ca2+-activated K+ channels in pig pancreatic acinar cells by Ba2+, Ca2+, quinine and quinidine. Biochim Biophys Acta. 1985 Oct 10;819(2):249–257. doi: 10.1016/0005-2736(85)90180-4. [DOI] [PubMed] [Google Scholar]
  21. Kakei M., Kelly R. P., Ashcroft S. J., Ashcroft F. M. The ATP-sensitivity of K+ channels in rat pancreatic B-cells is modulated by ADP. FEBS Lett. 1986 Nov 10;208(1):63–66. doi: 10.1016/0014-5793(86)81533-2. [DOI] [PubMed] [Google Scholar]
  22. Kakei M., Noma A. Adenosine-5'-triphosphate-sensitive single potassium channel in the atrioventricular node cell of the rabbit heart. J Physiol. 1984 Jul;352:265–284. doi: 10.1113/jphysiol.1984.sp015290. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Kakei M., Noma A., Shibasaki T. Properties of adenosine-triphosphate-regulated potassium channels in guinea-pig ventricular cells. J Physiol. 1985 Jun;363:441–462. doi: 10.1113/jphysiol.1985.sp015721. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Kurachi Y., Nakajima T., Sugimoto T. Role of intracellular Mg2+ in the activation of muscarinic K+ channel in cardiac atrial cell membrane. Pflugers Arch. 1986 Nov;407(5):572–574. doi: 10.1007/BF00657521. [DOI] [PubMed] [Google Scholar]
  25. Latorre R., Vergara C., Moczydlowski E. Properties of a Ca2+-activated K+ channel in a reconstituted system. Cell Calcium. 1983 Dec;4(5-6):343–357. doi: 10.1016/0143-4160(83)90013-1. [DOI] [PubMed] [Google Scholar]
  26. Marty A. Blocking of large unitary calcium-dependent potassium currents by internal sodium ions. Pflugers Arch. 1983 Feb;396(2):179–181. doi: 10.1007/BF00615524. [DOI] [PubMed] [Google Scholar]
  27. McCann J. D., Welsh M. J. Calcium-activated potassium channels in canine airway smooth muscle. J Physiol. 1986 Mar;372:113–127. doi: 10.1113/jphysiol.1986.sp016000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Misler S., Falke L. C., Gillis K., McDaniel M. L. A metabolite-regulated potassium channel in rat pancreatic B cells. Proc Natl Acad Sci U S A. 1986 Sep;83(18):7119–7123. doi: 10.1073/pnas.83.18.7119. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Noma A. ATP-regulated K+ channels in cardiac muscle. Nature. 1983 Sep 8;305(5930):147–148. doi: 10.1038/305147a0. [DOI] [PubMed] [Google Scholar]
  30. Nowak L., Bregestovski P., Ascher P., Herbet A., Prochiantz A. Magnesium gates glutamate-activated channels in mouse central neurones. Nature. 1984 Feb 2;307(5950):462–465. doi: 10.1038/307462a0. [DOI] [PubMed] [Google Scholar]
  31. Payet M. D., Rousseau E., Sauvé R. Single-channel analysis of a potassium inward rectifier in myocytes of newborn rat heart. J Membr Biol. 1985;86(2):79–88. doi: 10.1007/BF01870774. [DOI] [PubMed] [Google Scholar]
  32. Praz G. A., Halban P. A., Wollheim C. B., Blondel B., Strauss A. J., Renold A. E. Regulation of immunoreactive-insulin release from a rat cell line (RINm5F). Biochem J. 1983 Feb 15;210(2):345–352. doi: 10.1042/bj2100345. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Rorsman P., Trube G. Glucose dependent K+-channels in pancreatic beta-cells are regulated by intracellular ATP. Pflugers Arch. 1985 Dec;405(4):305–309. doi: 10.1007/BF00595682. [DOI] [PubMed] [Google Scholar]
  34. Sakmann B., Trube G. Conductance properties of single inwardly rectifying potassium channels in ventricular cells from guinea-pig heart. J Physiol. 1984 Feb;347:641–657. doi: 10.1113/jphysiol.1984.sp015088. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Singer J. J., Walsh J. V. Large conductance ca-activated k channels in smooth muscle cell membrane: reduction in unitary currents due to internal na ions. Biophys J. 1984 Jan;45(1):68–70. doi: 10.1016/s0006-3495(84)84112-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Spruce A. E., Standen N. B., Stanfield P. R. Voltage-dependent ATP-sensitive potassium channels of skeletal muscle membrane. Nature. 1985 Aug 22;316(6030):736–738. doi: 10.1038/316736a0. [DOI] [PubMed] [Google Scholar]
  37. Standen N. B., Stanfield P. R., Ward T. A. Properties of single potassium channels in vesicles formed from the sarcolemma of frog skeletal muscle. J Physiol. 1985 Jul;364:339–358. doi: 10.1113/jphysiol.1985.sp015749. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Sturgess N. C., Ashford M. L., Carrington C. A., Hales C. N. Single channel recordings of potassium currents in an insulin-secreting cell line. J Endocrinol. 1986 May;109(2):201–207. doi: 10.1677/joe.0.1090201. [DOI] [PubMed] [Google Scholar]
  39. Trube G., Hescheler J. Inward-rectifying channels in isolated patches of the heart cell membrane: ATP-dependence and comparison with cell-attached patches. Pflugers Arch. 1984 Jun;401(2):178–184. doi: 10.1007/BF00583879. [DOI] [PubMed] [Google Scholar]
  40. Wong B. S., Adler M. Tetraethylammonium blockade of calcium-activated potassium channels in clonal anterior pituitary cells. Pflugers Arch. 1986 Sep;407(3):279–284. doi: 10.1007/BF00585303. [DOI] [PubMed] [Google Scholar]
  41. Yellen G. Ionic permeation and blockade in Ca2+-activated K+ channels of bovine chromaffin cells. J Gen Physiol. 1984 Aug;84(2):157–186. doi: 10.1085/jgp.84.2.157. [DOI] [PMC free article] [PubMed] [Google Scholar]

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