Characterisation of sulphonylurea and ATP-regulated K+ channels in rat pancreatic A-cells.
We have monitored whole-cell and single channel ATP-sensitive K+ (KATP) currents in isolated rat glucagon-secreting pancreatic A-cells. Tolbutamide produced a concentration-dependent decrease in the whole-cell KATP conductance (Ki = 6 microM) and initiated action potential firing. The K+ channel ope...
| Main Authors: | , , , , , , , |
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| 格式: | Journal article |
| 語言: | English |
| 出版: |
1999
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| _version_ | 1826271143108018176 |
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| author | Bokvist, K Olsen, H Høy, M Gotfredsen, C Holmes, W Buschard, K Rorsman, P Gromada, J |
| author_facet | Bokvist, K Olsen, H Høy, M Gotfredsen, C Holmes, W Buschard, K Rorsman, P Gromada, J |
| author_sort | Bokvist, K |
| collection | OXFORD |
| description | We have monitored whole-cell and single channel ATP-sensitive K+ (KATP) currents in isolated rat glucagon-secreting pancreatic A-cells. Tolbutamide produced a concentration-dependent decrease in the whole-cell KATP conductance (Ki = 6 microM) and initiated action potential firing. The K+ channel opener diazoxide, but not cromakalim or pinacidil, inhibited electrical activity and increased the whole-cell K+ conductance fourfold. ATP applied to the intracellular face of the membrane inhibited KATP channel activity with a Ki of 17 microM, an effect that could be counteracted by Mg-ADP and Mg-GDP. GTP and UTP did not affect KATP channel activity. Phosphatidylinositol 4,5-bisphosphate activated KATP channels inhibited by ATP after a delay of 90 s. In situ hybridisation demonstrated the expression of the mRNA encoding KATP channel subunits Kir6.2 and SUR1 but not Kir6.1 and SUR2. We conclude that rat pancreatic A-cells express KATP channels with the nucleotide-, sulphonylurea- and K+ channel-opener sensitivities expected for a channel formed by Kir6.2 and SUR1 subunits. |
| first_indexed | 2024-03-06T21:52:00Z |
| format | Journal article |
| id | oxford-uuid:4b9740f1-85fa-4f09-b227-20bc78d4facb |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T21:52:00Z |
| publishDate | 1999 |
| record_format | dspace |
| spelling | oxford-uuid:4b9740f1-85fa-4f09-b227-20bc78d4facb2022-03-26T15:44:33ZCharacterisation of sulphonylurea and ATP-regulated K+ channels in rat pancreatic A-cells.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:4b9740f1-85fa-4f09-b227-20bc78d4facbEnglishSymplectic Elements at Oxford1999Bokvist, KOlsen, HHøy, MGotfredsen, CHolmes, WBuschard, KRorsman, PGromada, JWe have monitored whole-cell and single channel ATP-sensitive K+ (KATP) currents in isolated rat glucagon-secreting pancreatic A-cells. Tolbutamide produced a concentration-dependent decrease in the whole-cell KATP conductance (Ki = 6 microM) and initiated action potential firing. The K+ channel opener diazoxide, but not cromakalim or pinacidil, inhibited electrical activity and increased the whole-cell K+ conductance fourfold. ATP applied to the intracellular face of the membrane inhibited KATP channel activity with a Ki of 17 microM, an effect that could be counteracted by Mg-ADP and Mg-GDP. GTP and UTP did not affect KATP channel activity. Phosphatidylinositol 4,5-bisphosphate activated KATP channels inhibited by ATP after a delay of 90 s. In situ hybridisation demonstrated the expression of the mRNA encoding KATP channel subunits Kir6.2 and SUR1 but not Kir6.1 and SUR2. We conclude that rat pancreatic A-cells express KATP channels with the nucleotide-, sulphonylurea- and K+ channel-opener sensitivities expected for a channel formed by Kir6.2 and SUR1 subunits. |
| spellingShingle | Bokvist, K Olsen, H Høy, M Gotfredsen, C Holmes, W Buschard, K Rorsman, P Gromada, J Characterisation of sulphonylurea and ATP-regulated K+ channels in rat pancreatic A-cells. |
| title | Characterisation of sulphonylurea and ATP-regulated K+ channels in rat pancreatic A-cells. |
| title_full | Characterisation of sulphonylurea and ATP-regulated K+ channels in rat pancreatic A-cells. |
| title_fullStr | Characterisation of sulphonylurea and ATP-regulated K+ channels in rat pancreatic A-cells. |
| title_full_unstemmed | Characterisation of sulphonylurea and ATP-regulated K+ channels in rat pancreatic A-cells. |
| title_short | Characterisation of sulphonylurea and ATP-regulated K+ channels in rat pancreatic A-cells. |
| title_sort | characterisation of sulphonylurea and atp regulated k channels in rat pancreatic a cells |
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