Nitric oxide donors increase cytosolic ionized calcium in cultured human intestinal epithelial cells.
We used fluorescence spectrophotometry, digital-imaging fluorescence microscopy, and the fluorescent dye, Fura-2, to measure the effects of several different nitric oxide (NO.) donors on intracellular levels of ionized calcium ([Ca2+]i) in cultured Caco-2BBe cells, a human enterocytic cell line. Incubation of Caco-2BBe cells with sodium nitroprusside (SNP) or isosorbide dinitrate for 2 h significantly increased [Ca2+]i. The effects of both agents were concentration dependent. The lowest concentrations of SNP or isosorbide dinitrate capable of increasing [Ca2+]i were .625 mM and 10 mM, respectively. Chelation of extracellular Ca2+ with 2 mM EGTA abrogated the increase in [Ca2+]i induced by SNP. In contrast, blockade of voltage-gated Ca2+ channels with 2 mM NiCl2 or 200 microM verapamil failed to affect SNP-induced alterations in [Ca2+]i. Using NBD-phallicidin to stain polymerized (F)-actin, we found that incubation of Caco-2BBe cells with SNP results in actin polymerization, particularly in the periphery of cells. We conclude that NO. increases [Ca2+]i and promotes actin polymerization in a cultured enterocytic cell line.
Tsuji
Y
Y
Department of Surgery, Beth Israel Hospital, Boston, Massachusetts 02215, USA.
Unno
N
N
Menconi
M J
MJ
Smith
M
M
Fink
M P
MP
D018938:Caco-2 Cells; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D006801:Humans; D007548:Isosorbide Dinitrate / Q000494:pharmacology*; D007700:Kinetics; D009532:Nickel / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009599:Nitroprusside; D009569:Nitric Oxide; D004533:Egtazic Acid; C022838:nickel chloride; D009532:Nickel; D014700:Verapamil; D007548:Isosorbide Dinitrate; D002118:Calcium