Abstract
In B cells from dispersed rat islet of Langerhans we have identified an inward rectifying voltage-independent K+ channel whose behavior parallels the metabolically regulated potassium permeability (PK) found in tracer flux and microelectrode recording studies. In cell-attached patches of membrane, the channel is closed when any one of several substrates (glucose, mannose, leucine, or glyceraldehyde) is added to the cell's bathing solution but is reopened on addition of an appropriate metabolic inhibitor, which prevents utilization of that substrate. In inside-out excised patches, a K+ channel with nearly identical kinetic features is closed by addition of micromolar concentrations of ATP to the "cytoplasmic" solution. The ATP sensitivity of channel activity is modified by addition of ADP, suggesting competition at a nucleotide binding site. These results suggest the presence of a metabolically regulated K+ channel gated by intracellular concentrations of ATP or the ratio of ATP/ADP concentrations.
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- 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]
- Ashcroft S. J., Weerasinghe L. C., Randle P. J. Interrelationship of islet metabolism, adenosine triphosphate content and insulin release. Biochem J. 1973 Feb;132(2):223–231. doi: 10.1042/bj1320223. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Atwater I., Dawson C. M., Ribalet B., Rojas E. Potassium permeability activated by intracellular calcium ion concentration in the pancreatic beta-cell. J Physiol. 1979 Mar;288:575–588. [PMC free article] [PubMed] [Google Scholar]
- 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]
- Dean P. M., Matthews E. K., Sakamoto Y. Pancreatic islet cells: effects of monosaccharides, glycolytic intermediates and metabolic inhibitors on membrane potential and electrical activity. J Physiol. 1975 Mar;246(2):459–478. doi: 10.1113/jphysiol.1975.sp010899. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Gadian D. G. Whole organ metabolism studied by NMR. Annu Rev Biophys Bioeng. 1983;12:69–89. doi: 10.1146/annurev.bb.12.060183.000441. [DOI] [PubMed] [Google Scholar]
- 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]
- Kaplan D. R., Colca J. R., McDaniel M. L. Insulin as a surface marker on isolated cells from rat pancreatic islets. J Cell Biol. 1983 Aug;97(2):433–437. doi: 10.1083/jcb.97.2.433. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McDaniel M. L., Colca J. R., Kotagal N., Lacy P. E. A subcellular fractionation approach for studying insulin release mechanisms and calcium metabolism in islets of Langerhans. Methods Enzymol. 1983;98:182–200. doi: 10.1016/0076-6879(83)98149-1. [DOI] [PubMed] [Google Scholar]
- 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]
- Pipeleers D. G., in't Veld P. A., Van de Winkel M., Maes E., Schuit F. C., Gepts W. A new in vitro model for the study of pancreatic A and B cells. Endocrinology. 1985 Sep;117(3):806–816. doi: 10.1210/endo-117-3-806. [DOI] [PubMed] [Google Scholar]
- 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]