Significance of Na/Ca exchange for Ca2+ buffering and electrical activity in mouse pancreatic beta-cells.
We have combined the patch-clamp technique with microfluorimetry of the cytoplasmic Ca2+ concentration ([Ca2+]i) to characterize Na/Ca exchange in mouse beta-cells and to determine its importance for [Ca2+]i buffering and shaping of glucose-induced electrical activity. The exchanger contributes to C...
| المؤلفون الرئيسيون: | , , , , , |
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| التنسيق: | Journal article |
| اللغة: | English |
| منشور في: |
1999
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| _version_ | 1826284960307216384 |
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| author | Gall, D Gromada, J Susa, I Rorsman, P Herchuelz, A Bokvist, K |
| author_facet | Gall, D Gromada, J Susa, I Rorsman, P Herchuelz, A Bokvist, K |
| author_sort | Gall, D |
| collection | OXFORD |
| description | We have combined the patch-clamp technique with microfluorimetry of the cytoplasmic Ca2+ concentration ([Ca2+]i) to characterize Na/Ca exchange in mouse beta-cells and to determine its importance for [Ca2+]i buffering and shaping of glucose-induced electrical activity. The exchanger contributes to Ca2+ removal at [Ca2+]i above 1 microM, where it accounts for >35% of the total removal rate. At lower [Ca2+]i, thapsigargin-sensitive Ca2+-ATPases constitute a major (70% at 0.8 microM [Ca2+]i) mechanism for Ca2+ removal. The beta-cell Na/Ca exchanger is electrogenic and has a stoichiometry of three Na+ for one Ca2+. The current arising from its operation reverses at approximately -20 mV (current inward at more negative voltages), has a conductance of 53 pS/pF (14 microM [Ca2+]i), and is abolished by removal of external Na+ or by intracellularly applied XIP (exchange inhibitory peptide). Inhibition of the exchanger results in shortening (50%) of the bursts of action potentials of glucose-stimulated beta-cells in intact islets and a slight (5 mV) hyperpolarization. Mathematical simulations suggest that the stimulatory action of glucose on beta-cell electrical activity may be accounted for in part by glucose-induced reduction of the cytoplasmic Na+ concentration with resultant activation of the exchanger. |
| first_indexed | 2024-03-07T01:21:41Z |
| format | Journal article |
| id | oxford-uuid:90906a8a-b98d-472e-b7ce-a72b51affeb0 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T01:21:41Z |
| publishDate | 1999 |
| record_format | dspace |
| spelling | oxford-uuid:90906a8a-b98d-472e-b7ce-a72b51affeb02022-03-26T23:12:30ZSignificance of Na/Ca exchange for Ca2+ buffering and electrical activity in mouse pancreatic beta-cells.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:90906a8a-b98d-472e-b7ce-a72b51affeb0EnglishSymplectic Elements at Oxford1999Gall, DGromada, JSusa, IRorsman, PHerchuelz, ABokvist, KWe have combined the patch-clamp technique with microfluorimetry of the cytoplasmic Ca2+ concentration ([Ca2+]i) to characterize Na/Ca exchange in mouse beta-cells and to determine its importance for [Ca2+]i buffering and shaping of glucose-induced electrical activity. The exchanger contributes to Ca2+ removal at [Ca2+]i above 1 microM, where it accounts for >35% of the total removal rate. At lower [Ca2+]i, thapsigargin-sensitive Ca2+-ATPases constitute a major (70% at 0.8 microM [Ca2+]i) mechanism for Ca2+ removal. The beta-cell Na/Ca exchanger is electrogenic and has a stoichiometry of three Na+ for one Ca2+. The current arising from its operation reverses at approximately -20 mV (current inward at more negative voltages), has a conductance of 53 pS/pF (14 microM [Ca2+]i), and is abolished by removal of external Na+ or by intracellularly applied XIP (exchange inhibitory peptide). Inhibition of the exchanger results in shortening (50%) of the bursts of action potentials of glucose-stimulated beta-cells in intact islets and a slight (5 mV) hyperpolarization. Mathematical simulations suggest that the stimulatory action of glucose on beta-cell electrical activity may be accounted for in part by glucose-induced reduction of the cytoplasmic Na+ concentration with resultant activation of the exchanger. |
| spellingShingle | Gall, D Gromada, J Susa, I Rorsman, P Herchuelz, A Bokvist, K Significance of Na/Ca exchange for Ca2+ buffering and electrical activity in mouse pancreatic beta-cells. |
| title | Significance of Na/Ca exchange for Ca2+ buffering and electrical activity in mouse pancreatic beta-cells. |
| title_full | Significance of Na/Ca exchange for Ca2+ buffering and electrical activity in mouse pancreatic beta-cells. |
| title_fullStr | Significance of Na/Ca exchange for Ca2+ buffering and electrical activity in mouse pancreatic beta-cells. |
| title_full_unstemmed | Significance of Na/Ca exchange for Ca2+ buffering and electrical activity in mouse pancreatic beta-cells. |
| title_short | Significance of Na/Ca exchange for Ca2+ buffering and electrical activity in mouse pancreatic beta-cells. |
| title_sort | significance of na ca exchange for ca2 buffering and electrical activity in mouse pancreatic beta cells |
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