Spatial and temporal Mg2+ signaling in single human tracheal gland cells.
The combined use of Mag-indo-1 probe and laser confocal UV-microspectrofluorometry allowed us to investigate the spatial and temporal dynamic changes of the Mg2+ variations in human tracheal gland (HTG) cells at the single cell level. Stimulation of HTG cells with either bradykinin, ouabain or extracellular high Mg2+ concentrations (up to 10 mM) induced increases in intracellular Mg2+ concentration [Mg2+]i. From a cytosolic basal concentration of 0.8 +/- 0.3 mM in a medium free of Mg2+, an increase in extracellular Mg2+ concentration from 1 to 10 mM, increased cytosolic [Mg2+]i from 1.4 +/- 0.6 to 1.8 +/- 0.8 mM after 10 min (p < 0.05). We also demonstrated using line-scanned spectral images within single cells, that the [Mg2+]i is distributed uniformally in the nucleoplasm, but in contrast, showed marked local differences among different cytoplasmic regions, thus suggesting a functional heterogeneity in the intracellular Mg2+ stores involved. The influx pathway for Mg2+ in HTG cells was not inhibited by verapamil and appeared to be independent of [Ca2+]i.
Sébille
S
S
Laboratoire de Spectroscopie Biomoléculaire, IFR 53, UFR de Pharmacie, Reims, France.
Millot
J M
JM
Maizières
M
M
Arnaud
M
M
Delabroise
A M
AM
Jacquot
J
J
Manfait
M
M
D001839:Bombesin / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D005456:Fluorescent Dyes; D006801:Humans; D007211:Indoles; D008345:Manganese / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D012015:Reference Standards; D015398:Signal Transduction; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014132:Trachea / Q000378:metabolism*
D005456:Fluorescent Dyes; D007211:Indoles; C088692:2-(4-(biscarboxymethyl)amino-3-(carboxymethoxy)phenyl)-1H-indole-6-carboxylic acid; D008345:Manganese; D010042:Ouabain; D001839:Bombesin; D001920:Bradykinin