Multiple sites of purinergic control of insulin secretion in mouse pancreatic beta-cells.
In mouse pancreatic beta-cells, extracellular ATP (0.1 mmol/l) effectively reduced glucose-induced insulin secretion. This inhibitory action resulted from a direct interference with the secretory machinery, and ATP suppressed depolarization-induced exocytosis by 60% as revealed by high-resolution capacitance measurements. Suppression of Ca2+-dependent exocytosis was mediated via binding to P2Y1 purinoceptors but was not associated with inhibition of the voltage-dependent Ca2+ currents or adenylate cyclase activity. Inhibition of exocytosis by ATP resulted from G-protein-dependent activation of the serine/threonine protein phosphatase calcineurin and was abolished by cyclosporin A and deltamethrin. In contrast to the direct inhibitory action on exocytosis, ATP reduced the whole-cell ATP-sensitive K+ (K(ATP)) current by 30% (via activation of cytosolic phospholipase A2), leading to membrane depolarization and stimulation of electrical activity. The stimulatory effect of ATP also involved mobilization of Ca2+ from thapsigargin-sensitive intracellular stores. We propose that the inhibitory action of ATP, by interacting with the secretory machinery at a level downstream to an elevation in [Ca2+]i, is important for autocrine regulation of insulin secretion in mouse beta-cells.
Poulsen
C R
CR
Department of Islet Cell Physiology, Islet Discovery Research, Novo Nordisk A/S, Bagsvaerd, Denmark.
Bokvist
K
K
Olsen
H L
HL
Høy
M
M
Capito
K
K
Gilon
P
P
Gromada
J
J
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D037361:Adenylate Cyclase Toxin; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D005089:Exocytosis / Q000187:drug effects; D005260:Female; D019204:GTP-Binding Proteins / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D007306:Insecticides / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D009570:Nitriles; D026023:Permethrin; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D011722:Pyrethrins / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000502:physiology*; D058472:Receptors, Purinergic P2Y1; D013873:Thionucleotides / Q000494:pharmacology; D014044:Tolbutamide / Q000494:pharmacology*; D014544:Uridine Triphosphate / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D037361:Adenylate Cyclase Toxin; D007306:Insecticides; D007328:Insulin; D009570:Nitriles; C546383:P2ry1 protein, mouse; D011722:Pyrethrins; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D006153:Guanosine Diphosphate; C017180:decamethrin; D026023:Permethrin; C023427:guanosine 5'-O-(2-thiodiphosphate); D000255:Adenosine Triphosphate; D014044:Tolbutamide; D010741:Phospholipases A; D054467:Phospholipases A2; D019204:GTP-Binding Proteins; D005947:Glucose; D002118:Calcium; D014544:Uridine Triphosphate