Glucose induces temperature-dependent oscillations of cytoplasmic Ca2+ in single pancreatic beta-cells related to their electrical activity.
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.
Department of Medical Cell Biology, University of Uppsala, Sweden.
B
B
Hellman
E
E
Gylfe
E
E
Grapengiesser
U
U
Panten
C
C
Schwanstecher
C
C
Heipel
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003592:Cytophotometry; D003593:Cytoplasm / Q000378:metabolism; D004553:Electric Conductivity / Q000187:drug effects / Q000502:physiology; D005947:Glucose / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D051379:Mice; D013696:Temperature
D005947:Glucose; D002118:Calcium