[Effect of heparin on the increase in intracellular calcium caused by inositol 1,4,5-triphosphate in airway epithelial cells].
We studied the effect of heparin on the inositol 1,4,5-triphosphate (IP3)-dependent increase in intracellular calcium (Ca2+) caused by ATP. The Ca2+ concentration ([Ca2+]i) in cultured epithelial cells from cow tracheas was measured by the fura-2 method. ATP (10(-4) M) stimulated IP3 production and caused a biphasic increase in [Ca2+]i a transient response and a subsequent sustained response. Heparin (l 100 U/ml) dose-dependently inhibited the ATP-induced increase in [Ca2+]i but had no effect on IP3 production. Dextran sulfate, a polysaccharide with negative charge density, had a similar inhibitory effect on the ATP-induced increase in [Ca2+]i. These data suggest that heparin inhibits intracellular Ca2+ mobilization by acting at a site "distal to" IP3 production, and that the mechanism of action of heparin may be related to its negative charge.
Kondo
M
M
First Department of Medicine, Tokyo Women's Medical College, Japan.
Tamaoki
J
J
Isono
K
K
Kanoh
S
S
Konno
K
K
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D006493:Heparin / Q000494:pharmacology*; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis / Q000502:physiology*; D014132:Trachea / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D006493:Heparin; D002118:Calcium