Glucose induces temperature-dependent oscillations of cytoplasmic Ca2+ in single pancreatic beta-cells related to their electrical activity |
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Authors: | B Hellman E Gylfe E Grapengiesser U Panten C Schwanstecher C Heipel |
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Affiliation: | Department of Medical Cell Biology, University of Uppsala, Sweden. |
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Abstract: | Glucose induces large amplitude oscillations of the cytoplasmic Ca2+ concentration ([Ca2+]i) in pancreatic beta-cells. The effects of temperature on these oscillations were examined by monitoring [Ca2+]i continuously in single beta-cells from ob/ob-mice using dual wavelength microfluorometry. The oscillations of [Ca2+]i disappeared when the temperature was increased above 42 degrees C and were reversibly inhibited below 30 degrees C. However, cooling did not prevent a glucose response in terms of the average rise of [Ca2+]i. Since patch clamp studies of single beta-cells have indicated a random occurrence of glucose-induced action potentials at room temperature, it was important to explore how the sugar affected the electrical activity at 37 degrees C. Using the cell-attached configuration of the patch clamp technique for such analyses, the action potentials were found to occur in bursts with durations similar to the large amplitude oscillations of [Ca2+]i. |
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