Glucose-induced Ca~2+ signals in rat pancreatic β cells

摘要

Using microfluorometry to assay intracellular Ca~2+, the influences of varied factors on glucose- induced Ca~2+ signals, such as glucose-induced initial decline phase (GIDP), Ca~2+ oscillation, and Ca~2+ release from internal stores, were investigated in single rat pancreatic β cells, Glucose was able to evoke GIDP even at non-stimulus concentration (5 mol/L), which is insufficient to induce Ca~2+ spikes. GIDP was dependent on neither membrane depo- larization nor extracelluar Ca~2+. However, GIDP was inhibited by thapsigargin, indicating a dependence on Ca~2+ up- take by Ca~2+ stores. The glucose-induced calcium oscillation was inhibited when external Ca~2+ was removed.