Pulsed electromagnetic fields affect the intracellular calcium concentrations in human astrocytoma cells.
Experiments assessed whether long term exposure to 50 Hz pulsed electromagnetic fields with a peak magnetic field of 3 mT can alter the dynamics of intracellular calcium in human astrocytoma U-373 MG cells. Pretreatment of cells with 1.2 microM substance P significantly increased the [Ca(2+)](i). The same effect was also observed when [Ca(2+)](i) was evaluated in the presence of 20 mM caffeine. After exposure to electromagnetic fields the basal [Ca(2+)](i) levels increased significantly from 143 +/- 46 nM to 278 +/- 125 nM. The increase was also evident after caffeine addition, but in cells treated with substance P and substance P + caffeine we observed a [Ca(2+)](i) decrease after exposure. When we substituted calcium-free medium for normal medium immediately before the [Ca(2+)](i) measurements, the [Ca(2+)](i) was similar to that measured in the presence of Ca(2+). In this case, after EMFs exposure of cells treated with substance P, the [Ca(2+)](i), measured without and with addition of caffeine, declined from 824 +/- 425 to 38 +/- 13 nM and from 1369 +/- 700 to 11 +/- 4 nM, respectively, indicating that electromagnetic fields act either on intracellular Ca(2+) stores or on the plasma membrane. Moreover the electromagnetic fields that affected [Ca(2+)](i) did not cause cell proliferation or cell death and the proliferation indexes remained unchanged after exposure.
Pessina
G P
GP
Institute of General Physiology and Nutritional Science, University of Siena, Italy. pessina@unisi.it
Aldinucci
C
C
Palmi
M
M
Sgaragli
G
G
Benocci
A
A
Meini
A
A
Pessina
F
F
D001254:Astrocytoma / Q000378:metabolism* / Q000473:pathology; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D003470:Culture Media; D004574:Electromagnetic Fields; D006801:Humans; D007700:Kinetics; D013373:Substance P / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D003470:Culture Media; D013373:Substance P; D002110:Caffeine; D002118:Calcium