Arachidonic acid induces an increase in the cytosolic calcium concentration in single pancreatic islet beta cells.
The insulin secretagogue D-glucose induces both accumulation of nonesterified arachidonic acid (35 microM) in pancreatic islets and a rise in beta cell cytosolic [Ca++]i. Arachidonate amplifies both voltage-dependent Ca++ entry in secretory cells and depolarization-induced insulin secretion. Here, arachidonate induced a biphasic rise in [Ca++]i of Fura-2AM loaded beta cells which increased with arachidonate concentration (5-30 microM), was reversed upon washout, and was unaffected by the arachidonate oxygenase inhibitor BW755C. The sustained phase of the rise was abolished by removal of extracellular Ca++ and amplified by depolarization with KCl. The accumulation of nonesterified arachidonate in islets stimulated by D-glucose may therefore promote the D-glucose-induced rise in beta cell [Ca++]i.
Ramanadham
S
S
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
Gross
R
R
Turk
J
J
D015772:4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D009543:Nifedipine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology
D005456:Fluorescent Dyes; D007328:Insulin; C049925:fura-2-am; D016718:Arachidonic Acid; D004533:Egtazic Acid; D015772:4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; D011189:Potassium Chloride; D009543:Nifedipine; D005947:Glucose; D002118:Calcium; D016257:Fura-2