[Effect of manganese on cytosolic free calcium concentration in cortical neurons].
OBJECTIVE
To investigate the change of free Ca(2+) in cytoplasma in the neurotoxicity of the manganese (Mn).


METHODS
The cortical neurons were separated from the neonatal Wistar rats and cultured in vitro. The neurons were grouped as the Mn-treated groups and the untreated group. The neurons in the Mn-added groups were incubated in the culture media containing lower, medium and high dosage manganese chloride (MnCl(2 x 4) H2O) with the concentration at 0.2, 0.6, 1.0 mmol/L respectively. Meanwhile, neurons in control were cultured in the normal culture media. All treatments stopped 24 h later. Neurons were labeled Ca(2+) sensitive prober, Fluo-3/AM. The fluorescence intensity of Fluo-3 combined with Ca(2+) was examined by LSCM (Laser scanning confocal microscope) and was treated by the picture analysis technique. The intensity was equal to the free Ca(2+) concentrations in cytoplasma of neurons.


RESULTS
MnCl(2) can induce free Ca(2+) overloaded in cytoplasma of neurons, but the increasing degree varied in MnCl(2) dosage. Cytoplasma Ca(2+) concentration in the moderate dosage The moderate dosage MnCl(2) group and the high dosage MnCl(2) group were significantly higher than that in the lower dosage MnCl(2) group and the control group (P < 0.05).


CONCLUSIONS
The Ca(2+) overload is involved in the neurotoxicity of manganese, and a dosage response relationship is found between the manganese chloride dose and Ca(2+) overload in cortical neurons.
Lu
Cai-ling
CL
School of Public Heath, Guangxi Medical University Nanning 530021, China.
Guo
Song-chao
SC
Chen
Wei-ping
WP
Kuang
Xiao-cong
XC
D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D008345:Manganese / Q000633:toxicity*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D008345:Manganese; D002118:Calcium