Extremely-low-frequency magnetic fields disrupt rhythmic slow activity in rat hippocampal slices
Bawin SM, Satmary WM, Jones RA, Adey WR, Zimmerman G. · 1996
View Original AbstractSinusoidal 1 Hz magnetic fields at 56 and 560 μT irreversibly destabilized rhythmic slow activity intervals in rat hippocampal slices, an effect that depended on nitric oxide.
Plain English Summary
Researchers used rat hippocampal slices to study how extremely-low-frequency (ELF) magnetic fields affect rhythmic slow activity (RSA), a brain rhythm associated with memory functions. Slices were exposed for 10-minute epochs to 1 or 60 Hz magnetic fields at intensities of 5.6, 56, or 560 μT, or were sham exposed. 1 Hz fields at 56 and 560 μT, but not at 5.6 μT, triggered irreversible destabilization of RSA intervals, while 60 Hz fields showed similar but not statistically significant trends. The field effects on RSA did not occur when nitric oxide (NO) synthesis was pharmacologically inhibited.
Why This Matters
RSA is a cholinergic brain activity that was induced in the hippocampal slices by perfusion with carbachol, a stable analog of acetylcholine. The researchers had previously found that nitric oxide, synthesized in carbachol-treated slices, lengthened and destabilized the intervals between successive RSA episodes. This earlier finding led the team to investigate whether ELF magnetic fields could trigger the same NO-dependent disruption of RSA. Field effects could still take place when extracellular NO, diffusing from its cell of origin to the extracellular space, was chelated by hemoglobin. All exposures took place in the presence of an ambient DC field of 45 μT at an angle of -66° from the horizontal plane. The researchers suggested that ELF magnetic fields exert a strong influence on NO systems in the brain and could modulate the functional state of a variety of neuronal ensembles.
Exposure Details
- Magnetic Field
- 0.0056, 0.056 and 0.56 mT
- Source/Device
- 1 or 60 Hz
- Exposure Duration
- 10 min
Exposure Context
This study used 0.0056, 0.056 and 0.56 mT for magnetic fields:
- 280x above the Building Biology guideline of 0.2 mG
- 56x above the BioInitiative Report recommendation of 1 mG
Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.
Where This Falls on the Concern Scale
Study Details
Our studies sought to determine whether ELF magnetic fields could couple directly with brain tissue and affect neuronal activity in vitro.
We used rat hippocampal slices to study field effects on a specific brain activity known as rhythmic...
Sinusoidal 1 Hz fields at 56 and 560 μT, but not at 5.6 μT, triggered the irreversible destabilizati...
These results suggest that ELF magnetic fields exert a strong influence on NO systems in the brain; therefore, they could modulate the functional state of a variety of neuronal ensembles.
Show BibTeX
@article{sm_1996_extremelylowfrequency_magnetic_fields_disrupt_322,
author = {Bawin SM and Satmary WM and Jones RA and Adey WR and Zimmerman G.},
title = {Extremely-low-frequency magnetic fields disrupt rhythmic slow activity in rat hippocampal slices},
year = {1996},
doi = {10.1002/(SICI)1521-186X(1996)17:5%3C388::AID-BEM6%3E3.0.CO;2-%23},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/(SICI)1521-186X(1996)17:5%3C388::AID-BEM6%3E3.0.CO;2-%23},
}