Cytosolic and intranuclear calcium signals in rat basophilic leukemia cells as revealed by a confocal fluorescence microscope.
A confocal fluorescence microscope with an argon-ion laser (488 nm) and a He-Cd laser (325 nm) was used to study spatial heterogeneity of the calcium signals in rat basophilic leukemia 2H3 cloned cell line (RBL-2H3). After stimulation with antigen (2,4-dinitrophenol-conjugated bovine serum albumin), fluo-3-fluorescence intensities increased in individual RBL-2H3 cells with different lag times. Time-dependent profiles of the fluo-3-fluorescence intensities resembled closely the patterns of the sequential fluorescence-ratio images of fura-2, which were used to measure the intracellular free-calcium concentration ([Ca2+]i) in individual RBL-2H3 cells using a conventional fluorescence microscope. The present results obtained using the confocal fluorescence microscope showed spatial heterogeneities of fluo-3-fluorescence intensities, suggesting the existence of spatial heterogeneity of [Ca2+]i in RBL-2H3 cells. That is, the results showed that calcium signals first occurred transiently at pseudopodia in RBL-2H3 cells, then the signals transferred to the central parts of the cells. In addition, from the fluorescence images of co-loaded Hoechst 33342 (bisbenzimide H 33342, a DNA-specific probe) which were produced by excitation with a He-Cd laser, it was found that the fluorescence images of the nucleus were quite similar to those of the calcium signals mentioned above. This suggested that the receptor-mediated calcium signals were transferred not only to the cytoplasm but also to the nucleus.
Nakato
K
K
Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
Furuno
T
T
Inagaki
K
K
Teshima
R
R
Terao
T
T
Nakanishi
M
M
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D005456:Fluorescent Dyes; D007700:Kinetics; D015471:Leukemia, Basophilic, Acute / Q000378:metabolism*; D008856:Microscopy, Fluorescence / Q000379:methods; D051381:Rats; D013997:Time Factors; D014407:Tumor Cells, Cultured
D005456:Fluorescent Dyes; D002118:Calcium