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CA 2+ MOBILIZATION IN THE HUMAN SUBMANDIBULAR DUCT CELL LINE A253
Author(s) -
Andersson Charlotte,
Zhang AiLing,
Roomans Godfried M.
Publication year - 2000
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1006/cbir.1999.0503
Subject(s) - thapsigargin , stimulation , purinergic receptor , endocrinology , medicine , chemistry , agonist , receptor , intracellular , calcium , biophysics , biology , biochemistry
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 β2‐adrenergic receptors, and a third pool not sensitive to ATP or isoproterenol.