TY - JOUR
T1 - Selective activation of Ca2+ influx by extracellular ATP in a pancreatic β-cell line (HIT)
AU - Geschwind, Jean François
AU - Hiriart, Marcia
AU - Glennon, Major C.
AU - Najafi, Habiba
AU - Corkey, Barbara E.
AU - Matschinsky, Franz M.
AU - Prentki, Marc
N1 - Funding Information:
This work was supported by grants DK-35914, DK-35913, DKo22122, DK-19525 from the National In-
Funding Information:
stitute of Health and grant 186435 from the Juvenile Diabetes Foundation.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1989/6/15
Y1 - 1989/6/15
N2 - The action of exogenous ATP on cytoplasmic free Ca2+ ([Ca2+]i) was studied in insulin secreting cells using fura-2. Stimulation of clonal pancreatic β-cells (HIT) with ATP (range 2-20 μM) evoked a sustained elevation in [Ca2+]i. ATP selectively promoted Ca2+ influx and not Ca2+ mobilization since (1) the effect required external Ca2+ and (2) was observed in cells in which internal stores were depleted with ionomycin (3) the rate of Mn2+ influx, measured as the quenching of the fura-2 signal, was accelerated by ATP. The action of ATP was unaffected by the voltage-sensitive Ca2+ channel blockers nifedipine and verapamil as well as by a depolarizing concentration of K+. The effect on [Ca2+]i was highly specific for ATP since AMP, ADP, adenosine 5′-[γ-thio]triphosphate, adenosine 5′-[β-γ-methylene]triphosphate, GTP and adenosine were ineffective. In normal pancreatic islet cells, both exogenous ATP (range 0.2-2 μM) and ADP induced a transient Ca2+ elevation that did not require external Ca2+. The nucleotide specificity of the effect on [Ca2+]i suggests that ATP activates P2y purinergic receptors in normal β-cells. Thus, ATP evokes a Ca2+ signal in clonal HIT cells and normal islet cells by different transducing systems involving distinct purinoreceptors. A novel mechanism for increasing [Ca2+]i by extracellular ATP is reported in HIT cells, since the nucleotide specificity and the selective activation of Ca2+ influx without mobilization of internal Ca2+ stores cannot be explained by mechanism already described in other cell systems.
AB - The action of exogenous ATP on cytoplasmic free Ca2+ ([Ca2+]i) was studied in insulin secreting cells using fura-2. Stimulation of clonal pancreatic β-cells (HIT) with ATP (range 2-20 μM) evoked a sustained elevation in [Ca2+]i. ATP selectively promoted Ca2+ influx and not Ca2+ mobilization since (1) the effect required external Ca2+ and (2) was observed in cells in which internal stores were depleted with ionomycin (3) the rate of Mn2+ influx, measured as the quenching of the fura-2 signal, was accelerated by ATP. The action of ATP was unaffected by the voltage-sensitive Ca2+ channel blockers nifedipine and verapamil as well as by a depolarizing concentration of K+. The effect on [Ca2+]i was highly specific for ATP since AMP, ADP, adenosine 5′-[γ-thio]triphosphate, adenosine 5′-[β-γ-methylene]triphosphate, GTP and adenosine were ineffective. In normal pancreatic islet cells, both exogenous ATP (range 0.2-2 μM) and ADP induced a transient Ca2+ elevation that did not require external Ca2+. The nucleotide specificity of the effect on [Ca2+]i suggests that ATP activates P2y purinergic receptors in normal β-cells. Thus, ATP evokes a Ca2+ signal in clonal HIT cells and normal islet cells by different transducing systems involving distinct purinoreceptors. A novel mechanism for increasing [Ca2+]i by extracellular ATP is reported in HIT cells, since the nucleotide specificity and the selective activation of Ca2+ influx without mobilization of internal Ca2+ stores cannot be explained by mechanism already described in other cell systems.
KW - (Rat pancreatic β-cell line (HIT))
KW - ATP, extracellular
KW - Calcium ion
KW - Receptor operated channels
KW - cytoplasmic
UR - http://www.scopus.com/inward/record.url?scp=0024401748&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0024401748&partnerID=8YFLogxK
U2 - 10.1016/0167-4889(89)90018-9
DO - 10.1016/0167-4889(89)90018-9
M3 - Article
C2 - 2543452
AN - SCOPUS:0024401748
VL - 1012
SP - 107
EP - 115
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
SN - 0167-4889
IS - 1
ER -