ATP-induced intracellular Ca2+ signals in isolated human insulin-secreting cells.
Using isolated beta-cells from human islets of Langerhans we have demonstrated that purinergic receptor agonists are functionally coupled to rises in the intracellular calcium ion concentration ([Ca2+]i). The effects of ATP, ADP and AMP have been examined over a range of concentrations, 0.5 to 500 microM. The actions of ATP were more potent than those of either ADP or AMP suggesting that a P2-type of purinergic receptor operates in these cells. Responses to ATP were concentration-related, but exhibited marked desensitisation at high concentrations (> 100 microM). Purinergic receptor agonists elevate [Ca2+]i by mechanisms that involve both Ca2+ influx and Ca2+ mobilisation from intracellular stores. The physiological significance of our data has been discussed, and related to previous studies carried out upon rodent and clonal insulin-secreting cells.
Squires
P E
PE
Department of Biomedical Science, University of Sheffield, Western Bank, UK.
James
R F
RF
London
N J
NJ
Dunne
M J
MJ
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002469:Cell Separation; D016257:Fura-2; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007425:Intracellular Membranes / Q000378:metabolism*; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D015398:Signal Transduction
D007328:Insulin; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D002118:Calcium; D016257:Fura-2