Nov 15, 1989

Fluorescence ratio imaging of cytosolic free Na+ in individual fibroblasts and lymphocytes

The Journal of Biological Chemistry
A T HarootunianR Y Tsien

Abstract

New fluorescent Na+ indicators, SBFI (short for sodium-binding benzofuran isophthalate) and SBFP (short for sodium-binding benzofuran phthalate) (Minta, A., and Tsien, R. Y. (1989) J. Biol. Chem. 264, 19449-19457), were tested in Jurkat tumor lymphocytes and in REF52 rat embryo fibroblasts. Both dyes could be introduced by direct microinjection. However, when cells were incubated with the tetra(acetoxymethyl) esters of the dyes, only SBFI gave intracellular loading that was reasonably responsive to [Na+]i. Because some compartmentation of the SBFI was visible and because the indicator properties are somewhat affected by cytoplasm, the relationship between intracellular free Na+ [( Na+]i and the 340/385 nm excitation ratio of the indicator was calibrated in situ using poreforming antibiotics to equilibrate cytosolic [Na+] [( Na+]i) with extracellular [Na+]. The excitation ratio was sufficiently sensitive to resolve small changes, less than or equal to 1 mM, in [Na+]i in single cells. Basal [Na+]i values in lymphocytes and serum-starved fibroblasts were 9.4 and 4.2 mM, respectively. As expected, large increases in [Na+]i were elicited by blocking the Na+ pump with ouabain or withdrawal of extracellular K+. Mitogens such as phytoh...Continue Reading

  • References
  • Citations

References

  • We're still populating references for this paper, please check back later.
  • References
  • Citations

Citations

  • This paper may not have been cited yet.

Mentioned in this Paper

Chloride Ion Level
sodium-binding benzofuran phthalate
Lymphoid Cells
Pandavir
Rumensin
Cell Nucleus
Fluorescence Spectroscopy
Gramicidin NF
Rats, Inbred F344
Amphotericin B Colloidal Dispersion

About this Paper

Related Feeds

BRAIN Initiative Cell Census Network (BICCN)

The BRAIN Initiative Cell Census Network aims to identify and provide experimental access to the different brain cell types to determine their roles in health and disease. Discover the latest research from researchers in the BRAIN Initiative Cell Census Network here.

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.