Spontaneous calcium oscillations in clonal endocrine pancreatic glucagon-secreting cells.
Measurements of the cytosolic calcium concentration in single cells of the clonal endocrine pancreatic glucagon-secreting cell line INR1 G9 revealed the existence of spontaneous calcium oscillations in 20-70% of these cells. Inhibition of these spontaneous oscillations by thapsigargin as well as the phospholipase C inhibitor U 73122 demonstrated involvement of calcium release from intracellular stores, probably mediated by a high basal activity of phospholipase C. Removal of extracellular calcium but not the L-type calcium channel antagonists verapamil or nifedipine terminated the spontaneous oscillations, suggesting that calcium influx by a pathway distinct from L-type channels contributed to the oscillations. Similar spontaneous calcium oscillations could be the pacemaker of pulsatile glucagon release in endocrine pancreatic A-cells.
Bode
H P
HP
Department of Pharmacology, Philipps University of Marburg, Germany.
Yule
D I
DI
Fehmann
H C
HC
Göke
B
B
Williams
J A
JA
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000470:Alkaloids / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D005934:Glucagon / Q000378:metabolism*; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011760:Pyrrolidinones / Q000494:pharmacology; D019311:Staurosporine; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors
D000470:Alkaloids; D004963:Estrenes; D011760:Pyrrolidinones; D013729:Terpenes; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D015124:8-Bromo Cyclic Adenosine Monophosphate; C016276:8-bromocyclic GMP; D019284:Thapsigargin; D005934:Glucagon; D011493:Protein Kinase C; D010738:Type C Phospholipases; D006152:Cyclic GMP; D019311:Staurosporine; D002118:Calcium