Glucose-induced oscillations of intracellular Ca2+ concentration resembling bursting electrical activity in single mouse islets of Langerhans.
Intracellular Ca2+ levels were monitored in single, acutely isolated mouse islets of Langerhans by dual emission Indo-1 fluorometry. High-frequency (3.1 min-1) [Ca2+]i oscillations with a brief rising time (1-2 s) and 10 s half-width ('fast' oscillations) were detected in 11 mM glucose. Raising the glucose concentration to 16.7 mM increased the duration of these oscillations, which were otherwise absent in 5.5 mM glucose. [Ca2+]i waves of lower frequency (0.5 min-1) and longer rising time ('slow' oscillations) were also recorded. The data indicate that "fast" oscillations are directly related to beta-cell bursting electrical activity, and suggest the existence of extensive networks of electrically coupled cells in the islet.
Valdeolmillos
M
M
Department of Physiology, School of Medicine, University of Alicante, Spain.
Santos
R M
RM
Contreras
D
D
Soria
B
B
Rosario
L M
LM
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005110:Extracellular Space / Q000502:physiology; D005947:Glucose / Q000494:pharmacology*; D066298:In Vitro Techniques; D007515:Islets of Langerhans / Q000502:physiology*; D051379:Mice; D010507:Periodicity
D005947:Glucose; D002118:Calcium