Activation of Ca(2+)-dependent K(+) channels contributes to rhythmic firing of action potentials in mouse pancreatic beta cells.
1999 (English)In: The Journal of General Physiology, ISSN 0022-1295, Vol. 114, no 6, 759-70 p.Article in journal (Refereed) Published
We have applied the perforated patch whole-cell technique to beta 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 Ca(2+) influx but unaffected by apamin and charybdotoxin, two blockers of Ca(2+)-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 Ca(2+)-activated K(+) current plays an important role in the generation of oscillatory electrical activity in the beta cell.
Place, publisher, year, edition, pages
1999. Vol. 114, no 6, 759-70 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-161883PubMedID: 10578013OAI: oai:DiVA.org:uu-161883DiVA: diva2:457774