title: CA(2+) mobilization in the human submandibular duct cell line A253.
abstract: Ca(2+)mobilization induced by ATP, isoproterenol and the Ca(2+)-ATPase inhibitor thapsigargin in the human submandibular duct cell line A253 was investigated using the Ca(2+)-sensitive fluorescent indicator fura-2. ATP and isoproterenol increased cytosolic free Ca(2+)([Ca(2+)](i)) and subsequent exposure to thapsigargin after ATP or isoproterenol stimulation caused a further increase in [Ca(2+)](i). However, ATP and isoproterenol were not able to elicit a further increase in [Ca(2+)](i)after exposure of the cells to thapsigargin. Relatively few cells reacted to isoproterenol stimulation, but nearly all cells reacted to isoproterenol if ATP was added together with, or prior to isoproterenol stimulation. Moreover, the effect of ATP was potentiated by prior or simultaneous addition of isoproterenol. Furthermore, ATP decreased [Ca(2+)](i)in the presence of thapsigargin probably due to agonist-induced export of intracellular calcium. The results may suggest the existence of three thapsigargin sensitive pools; one opened by ATP acting through P(2)-purinergic receptors and IP(3), one opened by isoproterenol acting through beta2-adrenergic receptors, and a third pool not sensitive to ATP or isoproterenol.
authors.affiliation: Department of Medical Cell Biology, Uppsala University, Sweden. Charlotte.Andersson@medcellbiol.uu.se
authors.forename: C
authors.initials: C
authors.lastname: Andersson
authors.forename: A L
authors.initials: AL
authors.lastname: Zhang
authors.forename: G M
authors.initials: GM
authors.lastname: Roomans
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D009479:Neuropeptides / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D058910:Purinergic P2 Receptor Agonists; D018987:Salivary Ducts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013363:Submandibular Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019284:Thapsigargin / Q000494:pharmacology
chemical_list: C495401:ADCYAP1 protein, human; D000318:Adrenergic beta-Agonists; D004791:Enzyme Inhibitors; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D058910:Purinergic P2 Receptor Agonists; D015124:8-Bromo Cyclic Adenosine Monophosphate; D019284:Thapsigargin; D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases; D007545:Isoproterenol; D002118:Calcium