Increase in intracellular Cd(2+) concentration of rat cerebellar granule neurons incubated with cadmium chloride: cadmium cytotoxicity under external Ca(2+)-free condition.
In order to examine the cadmium cytotoxicity unrelated to external Ca(2+), the effects of micromolar CdCl(2) on intracellular Cd(2+) concentration, cellular content of glutathione, and cell viability of rat cerebellar granule neurons were examined under normal Ca(2+) and external Ca(2+)-free conditions, using a laser confocal microscope with fluorescent probes, fluo-3-AM, 5-chloromethylfluorescein (CMF) diacetate, and propidium iodide. CdCl(2) (10-300 microM) dose-dependently increased the intensity of fluo-3 fluorescence. Exposure to CdCl(2) equally enhanced the fluo-3 fluorescence under both Ca(2+) conditions and MnCl(2) did not quench the CdCl(2)-enhanced fluorescence. The results indicate that the enhancement of fluo-3 fluorescence is due to the increase in intracellular Cd(2+) concentration. CdCl(2) at 100-300 microM decreased the intensity of CMF fluorescence, indicating the decrease in cellular content of glutathione. The population of cells stained with propidium (dead cells) was increased by 100-300 microM CdCl(2). Similar results described above were also observed under external Ca(2+)-free condition. It is suggested that some of cytotoxic actions of CdCl(2) on neurons are unrelated to external Ca(2+), one of main sources for increasing intracellular Ca(2+) concentration.
Nishimura
Yumiko
Y
Laboratory of Cellular Signaling, Faculty of Integrated Arts and Sciences, The University of Tokushima, Minami-Jyosanjima 1-1, Tokushima 770-8502, Japan.
Yamaguchi
Jun-Ya
JY
Kanada
Aimi
A
Horimoto
Kanna
K
Kanemaru
Kaori
K
Satoh
Masaya
M
Oyama
Yasuo
Y
D000814:Aniline Compounds; D000818:Animals; D002104:Cadmium / Q000378:metabolism; D019256:Cadmium Chloride / Q000633:toxicity*; D002118:Calcium / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D002531:Cerebellum; D005452:Fluoresceins; D005453:Fluorescence; D005456:Fluorescent Dyes; D005978:Glutathione / Q000378:metabolism; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D011419:Propidium; D051381:Rats; D017208:Rats, Wistar; D014966:Xanthenes
D000814:Aniline Compounds; D005452:Fluoresceins; D005456:Fluorescent Dyes; D014966:Xanthenes; D002104:Cadmium; C069306:5-chloromethylfluorescein; C059715:Fluo-3; D011419:Propidium; D005978:Glutathione; D019256:Cadmium Chloride; D002118:Calcium