Study of extremely low frequency magnetic fields-responding mechanism in neuron

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The biological effect of extremely low frequency magnetic fields (ELFMFS) remains controversial. Some epidemiological studies have indicated positive correlations between magnetic fields and various types of cancer or other disease, including neurological disorders. To clarify the biological effects of ELFMFs, we performed the screening of ELFMFS-responding genes by using microarray technique in nematode C. elegans, as a model organism, and carried out the RT-PCR analysis not only the genes with significant difference identified by microarray, but also the associative and relative genes with possibility of ELFMFs-responding genes. Moreover, we investigated chemotactic response to either diacetyl or CuSO_4 after ELFMFs exposing.unc-43, one of the identified genes, is known to function as calmodulin-dependent protein kinase II (CaMKII), that mediates Ca^<2+> signal transmission in the nervous system of C. elegans. We found that unc-43 mRNA was down-regulated (2.4-fold) under ELFMFs exposure by RT-PCR. Another related genes, tax-6 (Calcineurin), itr-1 (IP3R) and cnb-1 (Calcineurin) in Ca^<2+>-Calmodulin (CaM) pathway were significantly down-regulated, respectively. ckk-1 (CaMKK), crh-1 (CREB) and cmk-1 (CaMKIV) showed no significant decrease (P<0.1), though these genes were reported to be functioning in the CaM pathway,.In behavioral analysis, chemotaxis index to diacetyl decreased, also chemotaxis index to CuSO_4 was shown weakly defective in avoidance when exposed with ELFMFs.These results suggest that the ELFMFs exposure caused the expression changes of neuronal specific genes which are associated with a part of calcium signal cascades, and has affected spontaneous locomotoion in C. elegans.