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Activation of Ca2+-Dependent K+ Channels Contributes to Rhythmic Firing of Action Potentials in Mouse Pancreatic β Cells

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  • معلومة اضافية
    • بيانات النشر:
      Rockefeller University Press
    • الموضوع:
      1999
    • نبذة مختصرة :
      We have applied the perforated patch whole-cell technique to β cells within intact pancreatic islets to identify the current underlying the glucose-induced rhythmic firing of action potentials. Trains of depolarizations (to simulate glucose-induced electrical activity) resulted in the gradual (time constant: 2.3 s) development of a small (<0.8 nS) K+ conductance. The current was dependent on Ca2+ influx but unaffected by apamin and charybdotoxin, two blockers of Ca2+-activated K+ channels, and was insensitive to tolbutamide (a blocker of ATP-regulated K+ channels) but partially (>60%) blocked by high (10–20 mM) concentrations of tetraethylammonium. Upon cessation of electrical stimulation, the current deactivated exponentially with a time constant of 6.5 s. This is similar to the interval between two successive bursts of action potentials. We propose that this Ca2+-activated K+ current plays an important role in the generation of oscillatory electrical activity in the β cell.
    • الرقم المعرف:
      10.1085/jgp.114.6.759
    • الرقم المعرف:
      edsbas.CFF0B0C9